I'd welcome a flat top with a Magsafe ring around the edge so that when you put your phone on it to charge the display becomes the big Siri swirl.

It also wouldn't hurt to put a USB-C port in the back so you could plug in an SSD and use it as a time capsule.

This local storage could open up some useful features like Siri caching streaming media during the day so you can watch it locally in the evening at full resolution without worrying about flaky broadband. Apple could even partner with Microsoft to offer a Gamepass Streaming cache that meant the player needed less bandwidth during gameplay.