^ Good point.
^ As we can see the Astrodroid in Doug's original concept is much smaller in relation to the ship and Doug has also clearly designed in ample room for the shoulders and height. As conceptualised there are no technical issues, they are all down to how it was implemented by Lucas.
Where is this the full quote (In context) that keeps getting trotted out about young Doug wanting to redesign the X-Wings? Because it sounds to me exactly the sort of thing a young excited artistic kid would rush home and do after seeing Star Wars. I know I used to design and redesign SF stuff in my sketchbook for fun.
As I've said before, I love Doug Chiang's paintings as they have the style, the vibrance and the romance of McQuarrie's work. Glad he's on board for EpVII!