Personally, I would really like to see Valve add a video capture feature. Like how on Xbox and PlayStation, you can press a button to record the last 30 seconds of gameplay. Something like this is almost impossible to do conviently on Steam Deck and just Linux systems in general. Valve adding it in natively to the Steam UI would be absolutely amazing.
Anyway, what features or improvements would you like to see on Steam Deck?
EGPU would be amazing. Even if it had to use the Dock or something. Would make it so much more viable to play games on my tv at 1080p