I agree - more of a "Naval" rank game vs "Air" combat FPS Marines might want to run differently - but normally not going to see Colonel Marines running around with the ground forces.

The highest we ever had in our Light Infantry unit were SSgts and 1st LT (butterbar). Everyone else was up at battalion or higher and was a REMF.

Taxman

"Any group is weaker than a man alone unless they are perfectly trained to work together."
- Robert A. Heinlein, Starship Troopers