[@SilverPaw] In my mind there's little difference between an illusion and any other kind of magical attack. You attempt to manifest it, and it either succeeds or fails. Things like pure mind control are master-level spells that won't be in player hands for a long time if at all. I don't anticipate PvP having much presence in this RP, and I would expect that we're all mature enough to handle IC conflict in a reasomable and empathetic manner.

This is my personal philosophy but I don't really pay particular mind to the idea of being "overpowered" in freeform roleplay like this. RP is based on a social contract; if I can trust you to follow basic rules of RP etiquette, I should be able to trust you not to ruin the game with your character's powers.