Better phone integration for music and text messages. More options for scheduled charging (based on departure time? based on rates for ToU folks?)
As someone said upthread, being able to play back the sentry and dashcam footage on the screen would be useful. Maybe also play movies from the USB drive (when parked, of course.)
As much of a 360 visualization as the car can give. It won't be great forward, but it should be decent otherwise. The lower window where the Ultrasonics show up could have the visualization superimposed on it.
Waze on the main screen, or maybe a Tesla built equivalent using data from the AP NNs.
Supercharger queuing on arrival, and data showing which stall to choose if no unpaired options are free.