I wouldn't mind if they enabled the 120 Hz support with the new chipset. I like my TV but the framerate matching feature causes a few seconds of black screen each time I switch between and also drops the UI to 24 FPS. Would be nice if everything just ran at 120 FPS all the time, and since 24/30/60 are perfect frame multiples that's nice to. NTSTC content at 23.976 I'd hope the player would just speed up at that point, but even if not... judder at 120 Hz is better than at 60 Hz.

Also 6 GHz Wi-Fi would be nice. I had to run a cable to my 2 because the 5 GHz airspace where I am is too crowded to stream high quality movies via Infuse without occasional hitching. Same with the seek speed. Meanwhile my iPhone gets 2.9 Gbps of goodput at solid jitter on 6 GHz Wi-Fi.

There's probably some updates to the HDR standards. For me at least though the current one already supports what my TV does.

Also apps seem to assume "because hardware decode isn't available don't serve AV1" sometimes. As silly as that is with the CPU power in the AppleTV, at least that problem would go away with hardware support and they'd stop trying to serve a "compatible" SDR h.264 stream. Despite internet pessimism, sometimes the quality is also raised with more efficient codecs rather than just "the same quality at less bandwidth".