10.9 exclusive? I didn't realize.
That's... A really small audience. You have the skill to make a game that would work on more than one OS, why do you have to use SpriteKit all of a sudden? It's not like we're making super complex graphics. You're just doing what Apple wants, they want people to buy the new OS so they're releasing things like SpriteKit.
Besides, we could still use Tiled for maps, right?