I don't know about its game balance, but damn this is awesome! *throws up the horns*

Crowd surf is a little unwieldy as what defines a crowd in D&D? Outside of DM fiat, there is not a rule for it. You may want to rewrite the mechanic a little bit to clarify that or simply state when your square is surrounded on all 8 sides and at least two to four deep with obstacles and creatures, perhaps?

Cover Band is nifty, but the mechanic for when it is used is a little clunky. Change it perhaps to not being hit by it but just witnessing it and restrict its school usage, like in Repertoire, and say max level is 6? I dunno, I understand it as written, it's just a little clunky. Might just be me.

Love this though, rock :D

-X