Three main things for me. One would be a more nuanced costume and power animation system, as this is the aspect of the game that I've always heard the most people speak of with the most fondness when it comes to City of Heroes. The second would be more game content. I think we have plenty of powersets and overpowered characters but it would be nice to have more content to use them in in a variety of different ways. The last, and one of the most interesting to me, would be an overhaul of the AI system for critters, so that we could have a greater variety of player/critter/NPC interactions. This last one would probably be pretty challenging, but a new, more nuanced A.I. for critters and NPCs would really add a lot to the gameplay experience of this game.
