Note that, as a player, I tend to dislike "specialists" in all rpgs I play though specialization does tend to foster collaboration, which is part of the fun of rpgs.
That said, I think that in many situations Arts are fungible. If you need to fly, you can do it with MuCo(An) or with CrAu(Re). Then, once you choose your "magic style", seasons spent in developing other Arts are only marginally useful. In fact, xps in those Arts are even less useful, because thanks to Summae 1xp in a lowish Art can be gained more quickly.
Finally, let me note that the point you describe, when a magus has such high Art scores in his area of specialty (2-4 Arts) that there's little point in improving them, comes rather late in most sagas if at all. And at that point I think it's more fun to play the archmagus who knows everything hermetic about CrCo and sets out to break the limit of essential nature than the one who says "well, time to get some experience in Intellego Aquam!".
There is a difference between the extreme 30+ in two arts and 5 in every other, and the still specialised magus with some 10s and 8s alongside the 30s. The extreme specialist will only have the feeblest spells outside his favourite TeFo, and this cripples them in stories. Once you get to 8-10 in most arts, you can spontaneously cast most second magnitude spells, and you may have a good repertoire of fourth and fifth magnitude spells. That gives a lot more stage time, but as an archmage you are still a long way from being generalist.
I agree that your limit breaking specials is a fun concept, but it does not deserve a lot of stage time. And frankly, the stage time to bookkeeping ratio makes me consider giving up roleplaying in favour of fishing or sailing at that point.
But then, to break limits, what you need is moderate arts and extreme magic theory. You need to invent many experimental spells, but there is no need for high-level spells, so this point is rather moot. Inventing a level 100 ritual would be a better example.
It says "xp", not Advancement Total or Source Quality. Things like Affinity or Book Learner only improve the Source Quality or the Advancement Total.
Well, getting 1 xp in your favorite Technique every season you study some other Art, will mean it takes a decade or so to raise your score in that Technique when you already have a score of 30+
If I was really interested in raising that Technique, I would rather study it directly from Vim. Much more efficient.
Much more efficient, but also much more risky. But then, you get that xp in your favourite form when you study your favourite technique, and vice versa.
Being marketted as the generalist's virtue, it has a remarkable impact on the specialist ...
You could exclude the highest technique and highest form from the 1xp bonus? That would resolve this issue at the cost of making the virtue noticeably weaker.
I agree with Ezzelino regarding the XP comment. I believe most people consider Flawless Magic one of the stronger major virtues. That's only 5 XP a spell, and will likely give less XP than a minor virtue affinity, however, I don't seen anyone saying Flawless Magic needs a buff.
I imagine most specialists will spend the 1 season per other art with a summae to get the non specialist stuff to 6. A few years from gauntlet the Rego Mentem specialist magi can spont 10th level Rego Anything and Anything Mentem, and when the Rego and Mentem gets higher late campaign, 15th and 20th level spont easily. While not as versatile as the full on generalist, it gives 14 decent options for any problem.
Getting from 0 to 6 is generally a 1 season exercise, and it's a huge boost, +6. For a specialist's big 2 arts, they will be lucky to get a 10 XP source quality, and that 10XP will go part way towards a +1, so it's a good XP spend in regards to opportunity cost.
The next +6 is 57 XP. Probably at least 4 seasons,. This is the huge issue with the generalist. The generalist going from 6 - 12 in everything, has spent 855 XP, 12 years achieving nothing more than being able to cast level 25 spells, and sponting level 15 with a good dice roll.
The specialist for the same XP gain could increases his 2 affinity based arts from 6 to over 35. I appreciate the specialist would likely get less than 855 XP, as he will be studying tractatii as the high XP summae are too low level, but this is about how some XP is better than others.
Any major virtue focusing on buffing generalists needs to not get frightended by large XP numbers. An extra 20 or so XP in arts that most people wouldn't spend XP in, is not a big deal in the context of buffing generalists. The only key is stopping the virtue being exploited to get a lot of XP in already high arts.
On this I sort-of-agree. It's best suited to certain types of magi with a slightly-broader-than-usual Art portfolio. It's one of the reasons why I'd like to keep the virtue as Major well-suited to generalists, and have it provide a lot of xp but ensuring they can't be concentrated. Say, providing 1xp to every Art other than the one being studied, or more xps to the lowest Arts.
I would stress it's also something that goes beyond Arts. Ars Magica tends to favour the specialist in any field; including grogs. That's a combination of several aspects. First, you generally need relatively few abilities to cover a role, and very very few of them are the ones where a really high scores really matters. Second, experience rules allow you to focus all your experience into a narrow area. Third, although the mechanics are of diminishing returns, they are not diminishing fast enough (compare with ArM1-2-3 Art study, where once you were in your 20s in an Art it was really, really difficult to push it up). Fourth, many Virtues (Puissant < >, Affinity with < >, Cautious with < >, Learn < > from mistakes...) reward specialization even further.
I'd like to see more Virtues/mechanics rewarding "broader-built" characters.
Except that, beyond the 5 XP per spell learned, it also gives +100% xp spent on spell mastery, which is double what you would get for an affinity. That aspect of the virtue is not to be neglected.
Halving the time it takes you to gain Mastery in a spell is Awesome!!! Especially when many of the Mastery options get better the higher your Mastery. I have a Bjornaer with mastery 6 in Pilum of Fire. Not many enemies can withstand 7 instances of Pilum of Fire to their face. And it adds +6 to casting the spell, and +6 to Penetration, and a few other bonuses. On one occasion, I managed to hit and kill 3 harpies in one casting.
Exactly. My point is being reinforced. Not all XP boosts are the same.
6 is a bit of overkill, so lets go with a mastery 4 for an example. Level 4 mastery costs 50 XP. A flawless magic mage gets 27 bonus XP to get to 4. Let's say instead of the +27 going in to getting mastery to 4, instead there was double, +54 XP, however, the XP is in the form of 6 spells getting 9 XP. I think most would prefer the focused XP, even though it is less XP.
That is why I made my suggestion above, of 1 third of the XP you study to be given to Three of your Lowest Arts. It might seem like less than Elemenatlist. But it's benefit is that it upgrades your Lowest Arts, whatever they might be, so it can boost your Techniques as well as all Forms. And makes you a more rounded Magi. And because it boosts lowest arts, it's great to those who want to get an Apprentice ASAP, because it will be easier to get all your Arts to at least 5, so you don't give him deficiency, and likely face a charge.
A consensus has still not emerged on what a Major version should look like, although I do quite like the sound of @Red-Shadow-Claws's idea. The problem is that I am not sure what the long-term effect would be; the experience points would naturally shift around the Arts, and tend to flatten everything, but it is harder to predict what sort of magus you would get than it is with Elementalist. This sort of problem is even worse for experience-from-spells or spells-from-experience. If people want to try them out, I think they would be interesting, but I think they are too much of a change for an erratum.
So, this is my latest boring proposal.
Secondary Insight
Minor, Hermetic
Your method of magical study is especially versatile. When you spend a season studying one of the magical Techniques from a book, a teacher, or raw vis, you also gain a single experience point in any 4 Forms of your choosing. When studying one of the magical Forms, you also gain a single experience point in any 2 separate Techniques of your choosing. You may not put more than one bonus experience point into a single Art, and may choose different Arts to receive the bonus experience points in each season, even when continuing to study the same Art from the same source. These bonus experience points are not increased by Affinities or any other factors. This Virtue is especially suitable for generalist magi.
Looks about the power level of Book learner. Not bad.
My Verditius character would love it.
This bit bothers me though. Why?
It's super useful for specialists!
Eg. As long as I keep studying my favourite Art, I get "free" XPs to spend on the other type of Arts (ie, the Ignem specialist still gains XPs to put into the Techniques he'll need), and any time I study the other type of Arts, I can still put a few XPs into the Art I care about!
It even gives me a few XPs to throw at other Arts of the same type, so I can get to 5-6 and be ready to teach an apprentice, while wasting fewer seasons to study it!
To be honest, I consider it more useful for specialists than for generalists.
I would suggest to drop the last sentence, which I find misleading.
The magi who will really benefit from this, is those who have two favourite techniques and a couple of (ideally four) favourite forms. In other words, moderately specialised magi and not generalists.
Not terribly important of course, but I honestly do not understand why the sentence is useful.
though specialization does tend to foster collaboration, which is part of the fun of rpgs.