Please excuse my english, as it is not my mother language (and it is my first post on this forum; hello everyone!)
I have a little problem of game balance in my troupe, that I cannot solve by arbitrary deciding it doesn't work. I explain myself:
First problem: one of my player has focused on Magic Resistance; Puissant Parma Magica, Affinity Parma Magica, every single xp put in Parma Magica, and on top, mastering every possible harmful spell in order to take the "Double Magic Resistance" option in Mastery.
Then, he managed to invent spells that allow him to become intangible: transforming into a ghost, or transforming into air.
Second problem: another Magus who overuse the Invisibility/ Fly / Fireball combo.
If I wish so, I can put these guys in a lot of trouble, this is not the real problem. It lies at the fact that any possible opponent is not a threat to them; I could make one so, but he would be ridiculousely powerful ("Well, yes, he DOES have a 90 Penetration Total with his Lightning Bolt, why?"), and it would become a Cold War (that has already begun) in order to create the most powerful and most boring Magus possible.
The second problem can be solved easily, by using Demons, Faeries, or even a spell to locate invisible characters. But this combo is overpowered, boring and plain.
In short: I cant' make only political or investigation stories; sometimes, magi have to fight, but I cant' put any decent opponent to oppose them (and when I say decent, I mean not a character who'd better belong to the Dragon Ball Z series).