Stadia support

First and foremost, multiuser support.

I want more user and developer-friendly google play. Now google play admins for tv blocks web browsers since "android tv does not support web content". So there nor firefox, nor tvbro. Mybe other useful apps also blocked. Also from user side there are no user reviews nor "whats new" section. Very limited search possibilities - for example sometimes I need to search for d-pad supported games, or for apps localized to my local language, or want to sort results by rating, update time, popularity etc...

Nest Hub mode when it's idle.

The ability to pin shows you are watching to the front screen with a single row regardless of the app you are watching the show on. I use the Shield and its so many clicks to get back to a show I was watching it's just annoying.

Home screen customisations, Widgets..

User changing support.

Built in coffee maker.

An option to pin live channels. Also a new games tab on homescreen in google TV.

Support for PS3 Sixaxis controller without root.

Auto frame rate

Shortcut to shutdown timer

A tuner function with numbered channels..

PIN lock on apps

Factory option to disable the giant ad that is the LauncherX/GTV layout.

Picture in Picture is already supported since Android 7, though it's also app dependent, not all developers have supported this, maybe by laziness or they just think users don't need it.

Apps reportedly working are:

Plex

Live Channels

Duo

among a few others.

My top feature would be auto frame rate matching. Followed by PIP

1. my Shield already have PiP or am I missing something?

2. what do you mean about this? Like a DVR?

3. the Android TV UI has a list feature and I can put content there for watch later, works with almost everything (Netflix doesn't for some stupid reason).

4. Android TV already have a UI where you can discover stuff, old and new, even the infamous recommendation row.

Grid layout for watch list. Who thought a ve

Never ending scroll was a good idea?

AC-4 codec support, otherwise that fancy 4K Digital Tuner you bought wont be able to process sound from ATSC 3.0. I dont see many people rushing out to buy a $300 sound bar to handle it.

FireTV 4K, Raspberry Pi4, Chromecast w/GTV, Xiaomi Mi Box S, 2nd Gen nVidia Shield, all fail to process sound from ATSC 3.0 broadcasts.

Multi user profile support on Sony 2019 A9G OLED Android Tv

• Better Subtitle support across all apps: Some Android apps already do subtitles/captions well enough, but too many apps have poorly rendered or no text support at all, you should be able to use Androids' own text settings / options and have them consistently on every video app. Even Google's own TV app doesn't use it's own UI subtitle settings FFS!
• A video screensaver, something like Apple TV's Aerial (Google should have it's own version by now).
• Built-in control to override Landscape/Portrait orientation for misbehaving apps.
• Better support for peripherals like Mice/Airmice/Keyboards/Gaming Controllers, there is driver support but there is no Android control over the settings like speed/button mapping/cursor appearance.
• A feedback function, so users have the ability to submit issues and suggestions to Google for review, so they have a better idea of what needs fixing in the next patch; Microsoft uses this approach and it works very effectively.

An improved app store experience. Search doesn't really work at all.

I wouldn’t be surprised if the next Android TV update would be to the Google TV interface.

Why would you think there'll be another version of Android TV now they've moved on to Google TV?