I recently built a new word game (SparkWord) on top of GameKit and Game Center. Apple really needs to up its game for indie mobile devs because right now it's not close to where it needs to be for support.
I've been working on the Skillz SDK for awhile. If you're a game developer looking for a different way to add social interaction, competition, leaderboards, etc. you may want to check it out.
Thanks - it feels like a missed opportunity within Apple that I'm not sure they're going to get right. I had another friend message this morning saying there is probably a better solution here. Will check out Skillz.