What would we want in a new one? Slightly faster chip won't play any mainstream AppleTV uses any faster. Faster wifi won't make any difference in playback experience. The rumored FaceTime camera only really works if one places their AppleTV immediately above or below, CENTER of their TV. Etc.
IMO: after 2 or 3 generations of a 4K AppleTV, the next hop is 48 megapixel cameras in iDevices able to
optionally shoot 8K... and thus the typical need for a way to get that video to 8K TVs for those who already have one. Select Samsung phones could shoot 8K since 2020 and
iPhones were rumored to go there at least 2+ years ago.
And no, an AppleTV 8K doesn't force anyone to throw out their perfectly-good 4K or HD TV (better hardware will scale any video down just fine). And no, it wouldn't have to wait until everything in the iTunes Store is 8K. Etc. In my long experience here, whenever anyone brings up the next resolution tier with AppleTV, a crowd jumps in like it is useless to advance the hardware until every other possible thing is upgraded first... which of course makes ZERO sense because if everything was 8K in the iTunes Store today, there would be no way for anyone to watch any of it in 8K without 8K hardware to stream it to 8K TVs.
The hardware must lead and the software catches up. You can't have tomorrow's tech software doing anything on today's tech hardware.
In all other Apple things, we long for next gen chips, new gen graphics, faster, better, fastest, etc, EXCEPT this one thing where we cling to "good enough" like advancing this will hurt us in some way. 720p was "good enough" while pretty much everyone else went 1080p first... until Apple embraced 1080p. And then 1080p was "good enough" while pretty much everyone else went 4K first... until Apple embraced 4K. At each step, the next resolution was "stupid", useless, gimmick, that "no one can see", "the chart, the chart", blah-blah-blah... until Apple made the change... and then it's as if none of that was ever written and all is now fine at the new tier.
Besides giving 8K-capable next iDevices a path to send 8K video to 8K TVs (or 4K TVs or 1080p TVs), 8K capabilities would mean significantly better hardware inside for everything else too. So even the guy who will abhor the idea of an 8K AppleTV (until they release one) would benefit by hardware revved up to deliver it to others who are already setup for it. Those happy with the as is could keep enjoying the as is. Those happing shooting video in 4K or 1080p or 720p could keep shooting it. Those happy with streaming in 4K or 1080p or 720p or SD could keep streaming. Those with pinched bandwidth could keep choosing whatever they choose now. All would just have superior technology ready to roll with any upgrades to any obstacles slung.
I've been a massive fan of AppleTVs since the first gen. I have one hooked to every TV in my home and they double as "cable box" (with cable), DVRs, home movie players, CD juke box, photo albums, etc... getting tremendous use. Nevertheless, I feel little excitement for another 4K one slightly faster (would that be 4th generation 4K AppleTV?). Bring on the next hop and let everything & everyone else then try to catch up with Apple for a change... instead of Apple dragging in about last to the next resolution tier party.