You did some research before your first post. That's rare. Good start!
About the Omega GMT: I have wondered exactly the same thing. It would be much nicer with the silver ETA movement. Dealers don't make any changes to these watches, they come straight from the factory like that. Sometimes there's no logic with the reps. Nobody has figured out yet why they always put the dreaded misaligned bezel to the Seamaster replicas, either. They just do, and we have to live with that (and modify the watches to our liking).