I'm just going today, storm troopers are one of the most accurate gunslingers in the galaxy, according to Ben. The miss Luke and Lea (Spelling?) because they realize that they are more valuable alive than dead.
Also, the troopers being poor shots is explained. They're clones, of clones, of clones. The mind deteriorates when a clone is cloned so the first batch of stormtroopers were great shots, but each fresh batch were worse shots. So on and so forth until Luke's time, when they've been cloned so many times that they couldn't hit the broad side of Jehovah's mom.
Because James Bond shooters a and storm troopers are never able to hit the person they are trying to shoot, so neither would win because neither side will ever be able to hit the other side when shooting so no one will ever win
but that's okay I'll forgive you