Some characters that make fun Team-Ups are not necessarily well-suited to be player Heroes. Take Angel, for example. He’s all about looking really cool flying around with his awesome, giant bird wings. He’s ideal for a Team-Up design. You get to enjoy his powers as an accompaniment to a player Hero’s actions. But could Angel support more than one tree full of powers with that flying play-style? Would play be fun when your character spends a more-than-average amount of time off-screen? What about close, indoor environments? We’re not saying he’ll never be a playable Hero, but he demonstrates how a given character might lend itself better to being realized as a Team-Up than a playable Hero.
More on Marvel.com: http://marvel.com/news/video_games/26600/marvel_heroes_2016_roll_call_kamala_khan_miles_morales#ixzz4HWy4q5fy
Ouch.