Thanks to Olgert for the link!
Interesting. I just noticed that the Tank Commander doesn't have his own hatch to stick his head up and out of the vehicle. I wonder if that small little thing could affect vehicle performance. Screens and cameras are nice but seeing it with your own eyeball has always been prized. I know that Marine Tank Commanders even with the optics they have like to use eyeballs and binoculars. It might be changing with Army Tankers with the M1A2 and it enhanced systems so I don't know.