While i'm a videogamer at heart, I have tried and have no interest in gaming on the ATV. What I would like though is more speed as my 4th Gen is getting a little slow pulling up an app. I'm also been for sometime having a delay on my remote where I need to wait a full second before the 2nd click registers. Not a big deal really but kind of annoying. I don't have that delay using the TV remote app on my iPad so it's probably a software thing.OTHER THAN HDMI 2.1 there's very little that the Apple TV needs.
HOWEVER... With the launch of Apple's gaming subscription, there is a huge argument that we'll see the A12Bionic chip put in it. No interest for me as i've never played a video game in my life!
What would you like adding to Apple TV? I guess for me, iTunes offering all of their catalogue in Dolby True HD would be very now! That's my only criticism of iTunes - the volume is so low on their films! If i'm watching on my Mac, you have to have the volume on max to get a hold decent level. It's strange as Apple likes to think that it's the best with everything and yet, it's seriously bad in this area!
I didn't see any of the big guys on the list of developers (Take Two/Rockstar, Square-Enix, Ubisoft, EA, etc., etc.). Just a couple of old glories like Sega e Konami. And well, ok, they have got the creator of Final Fantasy. But it's a bit too little, a bit too late...In my opinion, the gaming service with the Apple TV will be no match against an Xbox or PS.