As for public skd, sure. But we've already been able to use AirPlay on games for a while. For years. It's obvious (for now) Apple's notion of a controller is the iOS device itself, vs. Amazon using a typical console controller.
I've been waiting for years (like a lot of people I suppose) for Apple to spring the ATV sdk on the public. Every year, every WWDC, disappointment. This year I'm not holding my breath.
Its like playing Counterstrike back in the 56k and >100ms ping days. Aka, not a twitch game. Might work for things like plants versus zombies or candy crush though. But things like infinity blade are not playable. I tried, and failed horribly and just ended up using the screen anyway.
Would be cool if they opened up the airplay sdk and atv as well though. I do like my appletv in general but playing games from my ipad or iphone is... at best frustrating.
Apple introduced standards for console style iOS game controllers last year. A handful of compliant controllers have been available for a while.