Based on the squadrons of guys in Stormtrooper gear I’ve seen marching around at cons, movie screenings, ect., I’m sure they can see fairly clearly. Luke couldn’t see because the uniform didn’t fit him. "aren’t you a little short for a Stormtrooper?"
Also, for the umpteenth time, they can aim n’ shoot just fine in the OT. “They let us go! It’s the only explanation for the ease of our escape.” If they killed the kids on the Death Star, they wouldn’t be able to track 'em back to Yavin.