Metroid. It's certainly in the grave after what Team Ninja did to it. Just give it back to Retro Studios, dammit. They made the Prime games with such an amazing artistic passion and attention to detail, imagine what they could do with today's graphics.
It would be tough, though. Tougher than it was turning Metroid in to a first person adventure game (which Retro pulled off flawlessly, by the way). It would be tough because something needs to be addressed about the Metroid games: why does her suit keep failing, and bringing us back to square one? Team Ninja tried to address this by making Samus a whiny peon that had to run through a volcano without the varia suit because some big strong man told her she had to. It was idiotic and threw the very idea of who Samus is in our faces. Not to mention the liberal re-writing of well-established events in the previous games just to make Metroid: Other M make sense. And also, yeah, we get it. Metroid: Other M = MOM. Bottle ship = a baby's bottle. The baby, the baby, the baby. God dammit, we get it, Samus is a "mom" and the metroid is her "child." Jesus, what a horribly written game.
So yeah, it would be difficult to justify Samus loosing all her suit powers for the millionth time, but ... gdammit, I just want more Metroid Prime.