DC comics (Booster Gold, Doomsday, Hush, Grant Gustin Flash, Steven Amell Arrow, and Zatana for example. You know, characters who've never really gotten minifigures before)
Same for Marvel (I want a Kamlala Khan minifgure, darn it!)
One Piece (admit it a minfigure of brook would be pretty cool)
And...I'm not sure what else I would like to see as a minifigure aeries to be honest.