You are forgetting multiple facts:
1) The Imperial laser fires a short burst, only a couple light-feet in duration, from the documentaries, and requires a long recharge so that it cannot serve as a laser hose, unlike an AK. The storm troopers cannot just sweep an arc. Personally, I think that the battle droids were better than the storm troopers of Luke's early adulthood.
2) Accurate shooting is more difficult than Westerns would have you believe. There are multiple stories of cops and suspects exchanging fire, emptying their pistols at each other at point blank range, and neither hitting the other.
3) Leia, at least, can have an unconscious Force field deflecting shots (maybe by confusing the aiming of her attackers); Luke and Vader, Obiwan Kenobi and other full Jedi obviously would have such, as would the secret master villain, Jar Jar Binks.
4) The Death Star was the first crack at its design, and had obvious flaws that a few less-than-genius ship designers would have handled at the start, but it was clearly one genius's project. Modern carriers depend mainly on their Carrier Group (including their planes, of course) for defense, and if you ever visited them, Frank Lloyd Wright's building had major problems as buildings rather than as works of Art that has led to almost all of them being museums of FLW's work rather than homes or office buildings.