I think I read / heard that there was a limitation with the "existing platform" as to why they could not offer the air suspension.
I've been in new Escalade and X7, from a driver experience I think the cockpit in both is better. Primarily because of the features (map, camera, etc.) available in the LCD gauge cluster. The Navigator is definitely behind here, can't see the map or really do a whole lot of customization here. However the Nav wins in my opinion for the other seats in terms of space / comfort compared to those. I went Navigator for (1) engine and (2) comfort for all passengers vs just driver toys.