You and I both want an app store for our Apple TV. Games galore and whatever fancies you. However, it's a no-go yet even as others experiment with it. I think I know partly why that is so.
Square Enix, despite having awesome titles still have not managed to make a buck last year on the consoles. That's Playstation, Xbox, and the Wii. It seems to be doing a better on mobile like on the iPhones and iPads. I'm sure developers will be pleased when Apple TV gets an app store.
Of course, it's anyone's guess. Apple has always been very careful about these sort of things. Until they figure out a perfect way for users to access apps, it won't happen.
In the post, SE blamed the mess that the console market is in. They blame the cost of doing business which inflates the prices of the games which users shied away from. Apple is very likely looking to avoid the console makers' mistakes.
I also believe that once Apple decides to launch the app store for Apple TV, gaming will be a major marketing ploy. Both Apple and publishers will have to sit down and figure out just how they can make sure users can stay engaged while not repeating any of the issues console makers have had to go through.