I like the idea of skill variation, it was a part of the original design, but never really got implemented because I've struggled with a good way to put it in. Right now everything, except the initial buffs, has a 100% success rate. Do you envision the tiered traits originating from the same base trait? (probably too easy to save/load to get what you want?) Or maybe several base traits that would advance to a respective full mage trait?
Originally I meant it to be a static point, like a limitation of one's skills that can't be expanded upon but I've been playing around with a lot of JecsTools mods and found a really nice implement of this design in the Force-Sensitivity mod. Basically it tiers up from any starting point and as you gain experience it changes the trait in relativity to your ability to use the force (or in this case, magic)
This happens in the trait order of Force Sensitive(Trees to Sith, Gray or Jedi, for your mod I'm particularly interested in seeing this utilized in terms of Pyromancer, Cryomancer, Clergy/Priest and so-on)
Then you could separate the Trees into the original ranks or inspire your own flavor.
So maybe your base (Able to use magic) trait could be along the lines of "Gifted"
Then you dedicate a trait to the idea of "This person knows 2 Ice spells but this is vastly overshadowed by the fact he knows 6 Fire spells, so he's a pyromancer primarily, but if he learned 5 more Ice spells that could change him to a Cryomancer"
Rank the traits: Prestigitator (1+ point in two or more skills equally, equilibrium class) Wizard (4+ points in two or more skills equally, equilibrium class) then you start banking point over 6+ into certain trees and see new traits form(-mancers stated above) and finally once you've learned all of the skills in one tree you become Master (Pyro/Cryo/Terra)-mancer, for example.
If you plan on letting all the spells be known by a single pawn then you could incorporate an Arch-Mage trait that basically means "I know as much magic as humanly possible."
It's probably too far outside the scope to make multiple tiers of mages for each skill line, ie master fire mage, adept fire mage, novice fire mage, especially if it varies the spell behavior. This has a way to blow up real quickly...
It might be in the realm of possible to make several global skills available to different trait levels, and/or some of the spells only available to higher tiers. Alternatively, I could introduce a spell success chance across all spells that could cause the spell to fizzle or, less likely, backfire. This could be tied to a global skill that would reduce the chance for spell failure.
You could even shelf the bonuses of each trait and just have it as an indicator class or flavor text for the user without affecting the abilities of spells and just have that inborn in the mod itself (85% chance of a successful tornado etc, 15% chance it fizzles out and uses half of the dedicated mana required to cast it and maybe add a cooldown)
"Wow my wizard turned into a clergyman, must be because of the healing spells I've been specializing into him."
As far as catalysts - I think if I did this, it would be a lot like the "infused" mod, that adds a unique property to items, instead of being a new item itself. Thoughts?
That's more like it, actually. Maybe just for the sake of the theme later on down the line add Quarterstaves that do roughly the blunt damage of clubs or a spellblade that closely resembles the vanilla stats of the new Ikwa melee?
If you're keen to it you could give pawns that are gifted+ a thoughtdef for wielding an infused weapon:
Powerful- "My <weapon> is letting off pulses of arcana, I feel like I could take a kingdom." +6 to mood
You know, in your own design, something to play around with until more suggestions come in to flesh this out the way you imagine it.
I'll consider something like an arcane study/altar/lab etc. I think this would include added functionality for jobdrivers, thoughts, etc in the game to allow a pawn to 'use' the furniture, not really familiar with those modules so not quite sure what the overhead would be.
Time to go knocking down modder's doors. Particularly Jecrell's! He has something similarly applied in his Cults mod for the altar and the forbidden research bench.