This is why XCOM 2 is KB&M only (I'm leaving it big so you can see it):
Please note how the UI is layed out, particularly the number of buttons, plus the collapsible tabs on the sides for extra info and tiny tertiary info in the bottom corners.
Now note that this is the most straightforward part of the game - controlling a single unit.
None of this would work on a console-style layout. It would need to be entirely redesigned to support both, which would most likely necessitate redesigning the game so it uses less buttons. In other words, a compromise of the original vision for XCOM 2.