Allow rear passengers to control their own heated seats, and maybe HVAC and music as well.
Most cars with rear heated seats have controls that rear passengers can reach. Some have separate HVAC zone and controls as well. A small touchscreen would be a super solution, very extendable with firmware, and fits Tesla’s MO.
Implemented with the new rear touch display with the mid-2021 S/X.
Giving them control through the App is no good either, as that means the driver/owner has to had their phone to the passenger(s) unlocked and/or give the passenger(s) the code to unlock their phone. Actual controls in the back would be much more preferable, and easier to use for the less tech-savvy passenger.