Penny Arcade has published an article outlining pretty much the same reasons I have for eying the Ouya suspiciously.
Of some note is this quote attributed to a tweet by Notch (I haven't seen the tweet myself): "See, the problem with Minecraft for the Ouya is that it's android, and our android version of Minecraft isn't exactly that super great..."
Anyway, the article is worth a read if only to temper the hype a bit.
Speaking of incentive to replay a game, Metal Gear Solid 4 will be getting trophies sometime soon. I'm sure people will cringe if they have to re-earn the Big Boss Emblem if there is a trophy for it.
I heard about that, too. My copy of MGS4 is still unplayed 4 years later, so it wouldn't be replaying for me--though I think I may actually stick with the Trophy-less version of the game.