I believe I've come through with a solid solution for the task of making the leap to Masterable dragon spells so that new dragon adventure schools can be added without giving the race too much power. The criteria I understood were as follows:
  • The abilities have to become masterable, but the quests must be preserved.
  • The quests cannot grant a masterable ability.
  • The conversion has to be roughly equal to players at all stages of quest completion


Given those, and a few explanations of what has been tried but not worked, plus what I've seen in game already- I think I have the solution: Proficiency passives. It seems quite clear that dragon abilities can have an 'if' variable, having more damage or an additional effect depending on stance (Bite, Claw Strike, Galewind). Therefore, I put forth this- instead of having the quest unlock the ability, have the abilities granted in a Masterable format upon leveling, with each one roughly equivalent to the 'proficient' previous rank. Then, have the dragon quests grant a PASSIVE, hidden if possible, that increases that weakened version to the intended power of the skill.

To give a precise example, take Gold Rage VII. 2 extra hits, 500% damage modifier, Cripple effect.
NEW: Gold Rage VII. 2 Extra Hits, 450% Damage Modifier. Cripple Effect Unchanged. Masterable.
Gold Rage Proficiency VII: Adds +50% Damage Modfier to Gold Rage for a total of 500%.
I've refined this method down to offer the LEAST fiddly method possible for Gold Rage- some skills do have different range increases per rank, and I will volunteer to PERSONALLY sort through the math for every ability that would be affected, should the devs choose to use this method.
If stances work the way I believe, then a passive like this would simply need to check for the Proficiency passive with the rule "IF Proficiency<Ability> => <Ability Rank> THEN (Function at full power), ELSE (Function at reduced power)", which is what I understand Stances to do.

I earnestly think this solves every problem with the methods of transition tried so far, preserving the questing and leveling experience while -also- improving the leveling experience for newer players- if, for some reason, an ability gets neglected for a little while, say three ranks worth of levels, it will still get a slight rise in power to smooth out the growing Dragon's kit while still being rewarding to quest/have quested for.