I'd like to see 2-3 usb-c ports. Use "adapters' instead of the proprietary multi/mini, potential for gps, connectivity to monitors, ethernet, power in/out. AS grooves. Not sure they can solve the rear panel swivel/tilt/articulate concerns that would make all happy. If not putting dials and wheels on the top left, add a hot or cold shoe. Maybe move the flash sync port to the front.
A new sensor could be faster, adding resolution could impact power draw, file size, dynamic range, noise, all of which are already acceptable or catastrophically bad.
Don't grow the body size if possible.