I'm on record as being one fast casting is only for defense. Period. You can fast cast an offensive spell in an offensive manner, if you'd like, but it won't arrive at the opponent before their spell gets to you, so their spell does whatever to you, and your PoF does whatever to them. You can fast cast a PoF at a Mighty Torrent of Water, too, of course.
I guess I'm even one step from you:
Fast Cast is only for defense against supernatural effects. You can do as many in a round as you need to, to your limits.
Spells cannot be fast cast.
Maybe get rid of the penalties for fast casting, with fast cast total becoming Parma + (TeFo spont Total). A magus with Parma 5 can defensively fast cast against effects up to level 10 with impunity. An experienced magus can FC with impunity against up to level 20. A fatiguing FC lets him defend up to level 35. Specialists and Diedne do better. Cautious with Parma becomes interesting.
Cautious with Parma Magica becomes possible. 
Hmmm. One think I'd change of Parma is to make it ablative. In this way, even a very weak magus can resist a very powerful attacker, but not for very long; at the same time, a group of weak opponents can eventually bring down a powerful one.
How about the following? It has a number of side effects, but I consider all of them positive.
- Magic Resistant beings have a Resistance Score (RS), and pool of Resistant Points (RP).
- RP can never exceed RS, and can never fall below 0.
- RS and RP for supernatural creatures coincide, respectively, with Might Score and Might Pool.
- (This means that a creature that uses its powers offensively in general weakens itself).
- Parma gives you a RS equal to Parma score x5. No Form is added.
- To affect a target with a RS, you need a Penetration of 10 or greater; everything else is resisted harmlessly.
- A resisting target RP automatically spends RP to reduce Penetration of incoming effects.
- Each RP spent reduces Penetration by 10, until Penetration falls below 10, at which point 6 applies.
- A conscious being can always choose not to resist an effect, and thus avoid spending RP.
- RP regenerate at a rate of 1/round (so Might Pool regenerates faster than usual!).
- A being can Focus on defense in a given round to gain a pool of RP equal to RS/5 for that round only.
- These temporary RPs can be spent only in that round; any unspent at the end of the round are lost.
- Focusing on defense requires consciousness and precludes doing other stuff, save talking, walking slowly etc.
- (Exception: spending a fatigue level allows one to focus on defense and still take other actions that round).
- A character can always choose to focus on defense in response to an incoming attack (no surprises!)
- Hermetic magi and some supernatural creatures can extend their resistance to others.
- Parma can shield a number of targets equal to its score (including the magus).
- Each target who would be affected by a penetrating effect "consumes" RP independently.
- If multiple targets would be affected by the same effect, they can all be protected as if they were only two.
- The protector can choose to allow any effect through (and save the corresponding RP).
Example: Magus Iunior has Parma 3. He has a Magic Resistance of 15.
round 1: Magus Senior attacks Iunior by surprise with a Creo Ignem effect with Penetration 84. Iunior focuses on defense. This brings Senior's Penetration down to 54. It takes 5 more RP to bring Penetration down to 4 and negate the attack. Iunior's RP are now 10.
round 2. Iunior's RP regenerate to 11. Iunior tries to reason with Senior "Why are you attacking me?", while still focusing on defense. Senior irately casts another spell at Iunior, with Penetration 77. This brings Iunior's RP down to 7. "Why did you steal my staff?" cries Senior pointing behind Iunior.
round 3. Iunior chooses to spend a fatigue level and look behind; he recognizes Senior's fabled staff (the SG rules that this action precludes fully focusing on defense unless a fatigue level is spent). One more spell from Senior, Penetration 79. This brings Iunior's RP (which had regenerated to 8 ) down to a dangerous 4. "I don't know! I've never seen it before! Please, stop!".
round 4. "Liar!" cries Senior, and casts another Penetration 81 spell. Iunior realizes he has to focus on defense again, or be roasted. Even then, Senior's spell whittles his RPs down to a pitiful 0... so Iunior casts The Seven League stride and escapes to his sanctum.
Skipping over the entirety of the comments that follow to just focus on the main topic.
Parma is very very effective versus Hedge Wizards and Magic Beasts. Against magi? Much more effective than it was in previous editions.
Your mistake is using Philipius Noger as an example. Very poorly designed character, using half-considered 5th ed conventions without thinking the ramifications through. None of his Wards in his Talisman have Penetration for example. He is pretty weak as far as what I would expect from an Archmagus. Interesting concept, poorly executed. Similar problems can be found in all of the early fifth edition books.
Nixing books on Parma is also quite unfair. A score of 5 or 6 should be a minimum for a mature magus. An elder magus should be around 7 or 8. An Archmagus worth his salt should be at around 9 or 10 or higher. Especially a Flambeau magus.
Pick someone else, then. I wasn't using him to say how he wasn't designed effectively, and I agree he could have been better designed. I was using him as an example of having a Parma Score being a bit low for someone his age. Hugh of Flambeau has Parma MAgica 5 at +45 years. Ranulf gets to Parma Magica 6 at +6 years.
I took something away and I gave at the same time.
Marko, did you see where I said it should progress as an Art (Accelerated Ability, and practice grants 5xp for every season of practice. That means getting a Parma score of 5 is really 3 seasons of practice. Four seasons gets you to a score of 6, and only after that does one need to practice for more than one season to improve their score. Oh, and also Adventure experience. Stick 5 xp in Parma in every adventure where you get more than 5 xp, or give it the majority.
Maybe, but a quick perusal of Magi of Hermes doesn't support those scores, the highest score for Parma Magica is a score of 7 by Scipio of Merinita, no less, when he's +90.
After players exhaust the L6Q13 book on Parma Magica, to get to a score of 10 still requires 170 xp to get to a score of 10. If we assume that tractatus are available and have an average SQ of 10, it will take 10 of them and 17 seasons to get to a score of 10 from a score of 6.
Whereas, using the Arts progression requires a total of 11 seasons to get to a score of 10 (starting from Parma Magica 1), assuming it is a season of practice OR a seasons where adventure XP is 5 or more. I fail to see how that's unfair...
Hugh and Ranulf are both from Magi of Hermes.
Well, sure, if you don't allow Parma to progress as an Art, and you take books away, that's totally unfair.
Yes, you are THAT Flambeau guy.
Wow, way to frag the playtesters. Your argument is little more than he said they said. As it is, and it may be true what you say, but as it is, I'm less inclined to accept your argument, because to make it you need to denigrate someone else and their supposed play style.
So how high should a magi's Parma get?
If a magi spends one season's worth of exposure on Parma (2xp per year), with no other additions, and assuming Parma 1/5xp after gauntlet:
5 years: Parma 2/15xp
13 years: Parma 3/31xp
23 years: Parma 4/51xp
35 years: Parma 5/75xp
50 years: Parma 6/105xp
68 years: Parma 7/141xp
88 years: Parma 8/181xp
110 years: Parma 9/225xp
So the 'laziest' magi advancing only with exposure gets decently high.
What happens if a magus adventures once a year, and puts 5xp per year into Parma?
2 years: Parma 2/15xp
5 years: Parma 3/30xp
9 years: Parma 4/50xp
14 years: Parma 5/75xp
20 years: Parma 6/105xp
27 years: Parma 7/140xp
35 years: Parma 8/180xp
44 years: Parma 9/225xp
This is the kind of progression I'd expect from a Flambeau or Tytatlus magus. In both cases no serious effort is made to 'study' Parma - by which I mean hire a teacher or read Summae/Tractatus on Parma, but are accomplishing other things while growing Parma.
What about someone seriously studying Parma? We see above that magi will reach Parma 10 in their likely lifespan, so L5 Q15 Parma texts would exist unless the Order banned books on the subject. Better books might exist, but L5 Q15 is probably reasonable. I'll assume Parma magus studies the Summae 2 seasons a year. After that, tracking down Tratatus is necessary, but these won't be unlimited, so I'll assume 1 Q10 Tractatus per year (a low average).
1 year: Parma 3/35xp
2 year: Parma 4/65xp
3 year: Parma 5/75xp (Summae Limit)
6 year: Parma 6/105xp
10 year: Parma 7/145xp
14 year: Parma 8/185xp
18 year: Parma 9/225xp
That's pretty fast, and it's roughly 1/4 of the magus' time taken (50% the first 3 years).
The conclusion I draw from this is that that if your Parma is low, you aren't trying. Someone studying Parma 'part time' can get to a 9 in less than 20 years, and even the lab rat magus can easily advance his Parma by 1 per decade of life as a magus while doing lab rat stuff.
I think that's a bit simplistic.
If Parma isn't 9, I think it is safe to say you are paying attention to other things, probably the biggest other thing would be Magic Theory. Are you also not trying if your Magic Theory isn't also 9 in 20 years or less?
5 seasons to get to Level 5 in your example, and then to get from 5 to 9, assuming a Tractatus SQ of 10 on average is another 15 seasons, so 20 seasons out of 80 seasons, or 1/4 of the the total time available to a magus. By your logic, you're not trying as a magus if your Parma isn't 9 and your Magic Theory is 9, but that's a of time studying things that aren't your favored Arts AND not making stuff/doing stuff... I try and achieve a roughly 2 seasons of doing stuff for 2 seasons of study for my characters who aren't lab rats.
This, btw, is why I suggested free Parma xp, 1/Art xp.
Only Hermetics can have it, it continually develops and players can still take the fun stuff.
Sure, it is free, but all magi get it, the same way that the Gift is free and Hermetic Arts Opening, and the ability to spont, and....
Yeah, but who are they? What do they do? What are they all about?
Yes, yes I am :mrgreen:
Maybe I'll tell you when you answer my question, how my proposal (and no Parma books and progress as Arts) is unfair, especially when Parma then progresses much faster than it did under the current model...
My point is that it's reasonable to have magi 45 years past gauntlet with Parma 9 (5xp/year average) - it's not hard, you just have to compromise. Yeah, your Magic Theory will be a bit lower, and so will your arts, but Parma is GOOD to have. And that's a magi who's not a specialist in Parma, no Affinity, no Book Learner, nothing - even more, that magus might not even be sacrificing much of his useful time, as adventures don't always prevent laboratory work. A 'mature' magus with Parma 9 should not be viewed as 'exceptional', just as someone who put some effort into self-defense. The exceptional guy puts 25% of his time into it and gets Parma 9 in 20 years (without Book Learner or Affinity with Parma), but it's achievable.
NOT what I said. I said if your Parma is LOW you're not trying. If your Magic Theory is still a 3 after 20 years, yeah, you aren't trying either.
5 xp/year, in a single ability? So, a season of practice, as well as atleast one further XP from somewhere?
That seems like a lot, really.
I think his idea was abusing adventure experience to go one on ten-days-or-fewer adventure every year in which he had some creature with Might attempt to use its Powers on him and get resisted by his Parma.
Unless your plan is to hunt particularly aggressive magic bunnies, that plan is neither feasible nor realistic for any sane magus. Even the bunnies might have a dangerous surprise if you don't have a consistent place to find them. 
And they still might anyway, since the SG will want you to earn that adventure xp. Just a very unrealistic plan in most sagas, though not all.
I don't see the problem with Parma currently. You honestly don't need it all that high if you aren't planning to engage in a lot of combat. Sure, a Flambeau, Tytalus, or combat-focused magus of another house might want above a 9 in Parma, but for most characters that will be plenty. The fact is, 45 + Form MR is more than enough for any magus (even of the Arch variety) of any age to resist all but the weakest effects with three exceptions:
-
Powerful, high-Might creatures. Extremely rare in most depictions of Mythic Europe, and consequently most sagas. Even when they do appear, they're usually intelligent enough and there's enough mystery about how powerful you are and how much you can resist that non-combat options are aplenty. Don't back them into a corner or let yourself look too vulnerable and you'll live.
-
Anything involving multiple people, namely Ceremony and any other names given to group rituals. The levels and penetration on those things gets insane, not to mention that some traditions have wacky R/D/T options that let them hit the whole Order or something equally ridiculous. Importantly, such super displays would be extremely rare for reasons of resources and most traditions not getting along well enough to collaborate on this sort of thing, and more importantly to the discussion making Parma Magica an Accelerated Ability would have nothing on such a congregation unless you went Art-specialist on it, in which case the oldest Magi have crazy scores like 40 in it (200 + Form MR... And THAT isn't even necessarily enough) so the change makes no effective difference in this regard.
-
The last and biggest one, Hermetic opponents. Unless you're a hoplite, a gigantic jerk to Magi who might declare War, or your game takes place during the Schism War, this simply isn't something Magi need to worry about. There is, however, an exception to this, which I consider another reason not to do this: Certamen would be almost impossible if people's Arts are growing at the same rate but their Parma boost gets jacked way up. And of course, this works both ways. Order becomes much harder to maintain in the OoH if the people who rebel are this much better at resisting magic. Also consider that Trianoma and Bonisagus were the only ones who needed good MR to bring the Founders together. If we assume pre-MT-invention Bonisagus would've been treated as a Hedgie, he would've started with 120 xp in Parma, so pushing it to decent enough levels to resist the other Founders (not necessarily too high, though that's partially because I don't think the Founders would have had very high level/penetration effects in their traditions) might not have been so bad. Trianoma got it even luckier; Bonisagus taught just her and her sister, and combined with the +3 teaching bonus he was at least able to get her to 5 xp in a season through her (reportedly already quite high) pre-existing abilities. This leads me to believe that after the Ability was initially learned, he must've been able to provide her with a HUGE Teaching SQ. So she got it fast too (and he got Exposure, for whatever it would've been worth at that level). Point being, they got lucky and probably got quite high Parma Magica scores in relatively short times. The Founding was more reliant on them not hating each other's Gifts anyway, so it really makes quite a lot of sense.
In other words, an easier time reaching higher Parma Magica is vastly unecessary.
The problem is comparing Parma resistance against the Penetration of people who would have to be insane to take advantage of it. For everyone else, it's already plenty.
But that's kind of my point. If you want some ability to have a score of 9 in relatively short order you have to sacrifice a lot of things. Either virtues, or time to devote to the advancement, or some combination of the two. I don't see many magi getting to a score of 9 easily or quickly. I did see one player make a magus who had Parma Magica 10, but picked Puissant to get there, without Puissant he would have been Parma 8. He devoted a significant chunk of his experience points to Parma Magica. There's always so much more to do.
I'm just easing that burden, of devoting significant periods of time, just a bit. I have a hunch that many players will stop around a score of 5, or at least ratchet down the advancement of Parma after getting to 5.
I don't disagree that a score of 9 is enough, or really pretty high. I just don't see a lot of characters getting there, and with a lot of sacrifice, and oh by the way, there is still someone who can penetrate your MR, because the SG needs it as part of the story. Ezzelino makes a really good point here. Parma is something of a useless skill.
I'm skipping your points, I have nothing to add to them, nor do I entirely disagree with you, Vincent.
I wasn't only comparing Parma to the resistance of people who can achieve massive penetration scores, but let's assume for a moment that I were doing only that. The game effectively favors high penetration over high magic resistance. It is significantly more difficult to create a character who is very resistant to magical attacks than it is to make a character who is very capable with magical attacks. Why should that be? It's also arguably easier to make a magus who is skilled in counter magics, with high finesse and quickness to be able to shut down another magus's spells before they arrive, I made such a character and she eschewed Parma Magica, because (her/my theory) is that it was better to shut it down with a fast cast defense than to rely upon magic.
Thanks Vincent for your detailed arguments, I am in total agreement 
. At least, for all my games, too weak or too strong Parma was never an issue.
It can be explained purely through game mechanics and it has nothing to do with Bonisagus theory or whatever support Ars magic paradigm. There is nothing more boring from a drama perspective than balanced weapons vs armor, or offense vs defense. It only leads to escalation or boring stalemate.
By having it clearly unbalanced, it rewards those taking initiative or looking at alternative solutions & strategies.
I was recently reading FATE core rulebook and the author was clearly warning that it was a bad idea to offer protections as good (and as general) as the best weapons are, because very body is going to look for it, everybody wants to feel invicible and it becomes boring.
One adventure a year, one 'meh' tractatus every two years (Q10), one great tractatus every three years (Q15), an excellent teacher (Q20) every four. If you follow the advancement rules, it's 16.7% of your advancement, which isn't insignificant, but it's not a devastating amount. A lot of magi won't think it's worth it, but the combative type (like Hoplites) would definitely devote that kind of attention to it.
Spot on. Magi who want good/great Parma can achieve it, they just have to try.