These are the real questions

It helps unify them during parades

Well, it WAS a big stick.

So the because they have to outfit so many stormtroopers on a budget it's actually a high tech plastic so it's good enough and cheap. What it actually does is spread the energy across the body so it doesn't kill the trooper but it does knock them out.

The problem is likely due to the Empire being a dictatorship. There's quite a bit written about it but the Wikipedia article on "Workplace Democracy" is a good place to start.

Because inside the stormtroopers' armor, there are people. The Empire wants them to seem closer to machines, that are unable to make their own decisions.

When I was a kid I always thought that Stormtroopers were Robots, hence the exterior look

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