I would like to see following out of 5D4:
Touchscreen for DPAF focus
micro USB 3.0 cable support for faster cable transfers to PC
Yup, they will all be there.
Touchscreen for Pinch to Zoom image preview, quicker image proofing
Articulating screen if they are able to make it durable for creative shooting purposes
Dual SD slots that fully support UHS II standard
All quite possible since they're gimics that will attract feature-buyers...
Image quality improvement
If you're lucky...