How about adding a “Team Bonus”
For example:
Having Thor, IM, and Cap in your team would give you 10% power boost.
Another Example, having Hulk and She-Hulk (and maybe other hulks in the future) would give you 10% boost in defense.
This could add more strategy to the game (and possibly team diversity) and could only get better as more characters are introduced.
I actually had the same idea the other day and would really like to see something like this. I don’t think it would have to be a huge boost even a five percent bonus would be nice, so it doesn’t become too much. And there are lots of teams already in the game, the Avengers, Guardians, X-men, Defenders. Or just having one team get a bonus with events so that rotates around so you couldn’t always rely on your one team.