I would like to see another go at it. Just not another COH type one. DC and Champions online follow the COH formula but to me aren't quite as good.
Environment: Large open world with two cities, sewers, suburb, rural.
Players would be street level heroes and villains. A few heroes/Villians who are OP to be used to fight in groups. No Batman level heroes mixed in with Superman.
Content I would like to see.
No constant chaos with villian, heroes or problems just sitting around. Just have open world events from time to time that players can clean up.
Time based missions which players use phasing tech to have outdoor or indoor/outdoor missions. Of course indoor missions be instanced. Randomly generated group missions that require tactical cooperation. Mission outcomes effect your rep. PVP esport missions that pit heroes and villains against each other in scenarios.
That's all I can think of. Not sure why I have had the itch for a hero MMORPG and the two on the market just don't do.