New Heroes: Do you want 12 heroes a year again while neglecting things like story and modes?
Modes: New game modes, new terminals, new oneshots, essentially more content but at the expense of number of heroes released.
End game: More end game content in general.
Tweaking/Balanced/Updates: Going back to fix heroes dated apperances, powers and overall quality of life before focusing on new things.
Team ups: More new and varied team ups.
PVP: Do you finally want that released instead of more PvE content?
What do you want to focus on?
Personally I would like more content such as one shots and stories and modes. And I would like the modes to be more accessible. I think danger room is a ton of fun but I don't think it should be forced to be completed at level 60. Same with raids. I think you should be able to do raids at any level, just highest level gives best gear and is more difficult.
I think we have more than enough heroes and I think the amount for this year is perfect. So far GG and Elektra have been a lot of fun to play and they have updated several older to give better QOL. Personally I want more 1 shots. 1 shots allow for an arc to be played without having to add to the actual story element. Thinks like Avengers Vs X-men, Maximum Carnage, House of M, etc could easily be placed into a 1 shot and be made playable.