In keeping with the spirit of the game, I think it might be fun to have bonuses for themed teams - for example, if your team consists of all Avengers, or Dark Avengers, or anything else that’s possible (several future possibles like X-men or Fantastic Four will need a few more characters) you get either a generalized (like 10% across the board) or specific (Avengers get additional shield tiles on yellow matches, for example, while Dark Avengers get +20% on purple matches) bonus.
Since the boosts mean that these teams are already coded in, it might not be super-complicated. But it would add a dimension to team design that might be fun.