true, but most conventional sights are low to the gun, and not all soldiers are sent into the fire with a enhanced sight.
regardless if its EOTech or a reflex sights, the user might find difficulty in placing shots without the use of sights. (unless he has a 'gun cam' attached to his gun and a live feed moniter mounted to his helmet, of course)
Ok, well lets for arguments sake, assume, that if a soldier gets to wear a multi million dollar super suit, they are going to have whatever advanced weapon systems they want. There are also long eye relief scopes that have iron sights built on top of them for higher clearance.
I'm actually wearing a kevlar helmet & body armor as I'm writing this, and I really dont see any major problems with being able to aim proficiently. A gun cam is something I'd like to incorporate eventually, but that would be a lot more visually disorienting than you'd think, unless your using it to aim around corners, its just going to distract and disorient you as you move.