2. X-Men
We have X-Men games already, in all shapes and sizes. Hack and Slash games, MMO's, side scrolling arcade fighters and without counting the recent "X-men Destiny" we don't really have a mutant filled sandbox to play in. Unfortunate I know, but how many of you have ever played Prototype 2? Good wasn't it? You had to move around this monster infested city doing over the evil PMC thats cracking down on the critters and quarantining the entire city. You could eavesdrop and follow your target along the rooftops and be all stealth, or you could rush into a crowd of soldiers, sprout a blade out your arms and make the entire scene look like someone had been tap dancing on ketchup sachets. But the point is that the mechanics of the mutations and the way in which you get so much freedom of choice regarding your powers, abilities and the way you want to morph the character to suit you as a player, is something that if worked around in a decent developers soft and tender hands could translate beautifully to the X-Men universe. Maybe a "create your own mutant" would work well? If not then maybe you play as an entirely new character who has a sort of "behind the scenes" story? It's been done before with other franchises (Force Unleashed) and why not bring some of that to the X-Men universe? Not to mention theres about a billion cameos to drop in there. And I'd love to get to beat the Adamantium out of Wolverine at some point. Never liked him much.