I have been reading the MuVi Guidelines and I must say I find myself a bit puzzled. I will quote some parts of the guidelines and discuss them.
I find this quite restrictive and don't see where the game balance argument comes into play. This means that an Archmagus specialized in Vim would be unable to affect the most simple spontaneous spell cast by an apprentice (but he would well be able to dispell it). And how can you tell when a spell is being cast whether it is a spontaneous or a formulaic one ?
This means that you are unable to cast your MuVi spell in an inconspicuous way if you are not cooperating, as Fast Casting implies a firm voice and bold gestures. Again, I find this quite restrictive.
I can understand and back up that one. But in certain circumstances I don't see how it works.
a) Maga A casts a formulaic spell with a Concentration duration. Maga B fast casts a MuVi spell with a Concentration duration on the spell cast by Maga B. What happens it Magus B loses his concentration before Maga A ?
b) A Maga casts a formulaic spell with Diameter duration. Her sigil is red sparks at her fingertips when a spell is cast. She simultaneously casts Shroud Magic with a Momentary duration in order to suppress her sigil. As the duration of the MuVi spell is lower than the targeted spell, what happens here ?
Actually, it's quite the opposite. As-is, the archmagus of Vim can spont Vim spells as well as the archmagus of (Form) can spont (Form) spells. If you change this rule, however, then the archmagus of Vim can spont spells of any form as well as the archmagus of each (form). The reason is that the archmagus of Vim would be able to boost his own spontaneous spells by a magnitude or two in either range or duration with ease. Once you pass level 5, that's 5 or 10 spell levels saved. For non-fatiguing spontaneous magic, that's like having 25 or 50 more points in the two Arts being used (combined). For fatiguing spontaneous magic that's like having 10 or 20 more points in the two Arts being used (combined). Since we care about what can be reached here, we're looking at the upper limits. So the archmagus in Vim gets to spont all non-Vim spells as though he had somewhere between 20 and 50 bonus ranks, so between 10 and 25 in each Art. Let's lean towards the lower end since that's the power end, versus the high end being the replicable end, so perhaps a little under 15 is a good estimate. So allowing MuVi to affect spontaneous magic allows the Vim specialist to use spontaneous magic as though he had somewhere between 10 and 15 more points in every other Art. That practically makes him a specialist in every Art as far as spontaneous magic is concerned. Thus the imbalance.
Basically, the archmagus in vim, who has a vim spell level 25 and a MuVi level 50 can create any form level 25 spell and, if he has good concentration can boost it to level 30 with a level 30 MuVi "wizard's boost", "wizard's range", "wizard's penetration", "wizard's duration" spell.
In another saga, my vim magus will have that, allowing her to cast a level 25 spell, then transform it with a MuVi 50 into any other spell. The only restriction is that the "target" with a minuscule t (to distinguish from the Target which is the form used) remains.
No spont, and it's almost as good as any other specialist, doing any spontaneous spell she want, but without them being spontaneous.
Ah, yes, the risk of botching... cautious with concentration avoid it. Or a good familiar gold cord is useful.
The requisite "not casting it on spontaneous magic" is useful to prevent MutoVim on enemies spells (if they understand their formulaic spells are useless against your vim magus), but for your own spells, it's a true joke, which isn't a true obstacle IMO.
I would argue strongly against a single level 50 MuVi spell being able to do that. The MuVi guidelines are far from clear, but I would say:
The most important: "Note that a spell invented according to one of the guidelines below will change another spell in a specific way; it is not possible to invent a single spell which changes another spell however the caster wants." I don't see how you get past this rule with your proposed spell.
You won't be changing targets (as you mentioned), the Target, the Range, or the Duration with this guideline. It's not that the guideline couldn't handle some of those changes so much as you're already using the guideline to change Technique/Form. If you are going to allow alterations to the rest also, then surely you'll need more magnitudes.
Changing just one of the Technique or Form follows this guideline, too. I would expect changing both the Technique and the Form should require an extra magnitude. I could see troupes going either way on this one.
The point is that archmage sponts a spell of any technique/form and then MuVI to make diameter into day or moon. He sponts MuVI to change range and target as well. Suddenly what normally would be level 5 or 10 spont as he originally cast it (casting total of 10-20) is now having effect of level 20-30 spont. Anyone else without the MuVi spells would have to have casting total of 40-80. The second spont can affect (the spont MuVi) can be any form version of the boosting spell.
to give example: Magus sponts ReCo spell of level 5 (base 2, +2 voice, +1 diameter, needs casting total 10), he then casts a wizard's boost (formulaic for corpus) affecting that spont spell to raise it level 10 to change diameter to sun and then another wizard's boost to raise to sight. He now has a level 15 spont spell. If he wasn't a MuVi specialist with level 30 wizard boost for each form developed, he would have needed a 30 casting total in ReCo. Instead he needs a 10 casting total. This applies to any tech/form combination since he has all 10 wizard boost spells (mastered for fast cast, multicast)
basically he can add 5-10 levels easily to the level of the spont which becomes 10-20 extra casting total needed.
Better yet, he could just spont the muvi spells (it is his specialty and is arch mage, perhaps can get 50 casting total to spont without fatigue level 10) and boost level 4 spells (say base 3, range personal,diameter, individual) and boost it to touch/sun or level 10. this case now has casting total of 8 in any technique/form combination to have same impact as anyone else needing casting total of 20. Since it is all spont, a 4 in each technique, 2 stamina and confidence available and suddenly fails only on a 0 (botch). If he wants to exert himself with fatigue on the MuVi spont, it is a level 25+stress die MuVi so that level 4 spell could perhaps become level 20 with range/duration/target modifications. Now that each technique of 4 and 2 stamina effectively becomes equal to spont with casting total of 40 in every technique/form combination.
That's debatable. One rule is that you can't use MuVi spells on spontaneous magic. You're OK with that one. However, it's the wording of Wizard's Communion that's tricky. Wizard's Communion refers to "the level at which they know it." There is also no reference to actually having to cast the spell. My group focuses on it being a spell, so we play that you have to cast Wizard's Communion and it's the spell level cast that matters. (So we have some Mercurian magi who know it at levels they can't use yet.) So for us a spontaneous Wizard's Communion is fine. I would assume groups that focus on the "know" part instead of the spell part would not allow you use spontaneously cast Wizard's Communion. Hope that was helpful.
