you know who i think should be next? Jean Gray, it would even work perfectly with a premisse kinda like rogue, with her starting to lose control of her powers due to the dark phoenix, and rogue asks if you can help her, from there it could even evolve into a dual personality kind of thing, with jean being more sub, while the dark phoenix side being more dominant.
on the same aspect, it would also make sense to give the player a job, in something like a help group, it could be something like using his powers to help people like rogue(and jean here) cope with them, that way we could have more characters like jubilee, pixie or magma... or so many more!
finally, i wouldnt be against giving our character more status, and using them on "choose your own adventure" like missions, wouldnt even be that hard to implement, and would add alot to the game...