But if you believe the EU stories, Veers was killed whan a Rebel pilot crashed into his AT-AT's cockpit. Not so efficient when he's smeared across several thousand red hot chunks of metal, eh?
As for the stormtroopers, they're not so hot either. It makes you wonder how many shots it took to kill Owen and Beru, I bet they could have run all the way to Mos Eisely to get away if they'd tried.
Piett seemed like a nice guy though, a problem GL seems to have qwhen portraing some Imperials. Stormtroopers, on the whole, seemed like nice guys, and Piett always came off as a weary, worried admiral, running around to avoid death at the hands of Vader. I once wasn't very well-up on Star Wars, and I was convinced that the Millenium Falcon escaping at the end of ESB meant Piett's death, until I saw him in ROTJ when I looked closely.
In ROTJ at the request of fans, no less...
There is always this assumption that all Imperial characters are bad. GL wanted a very simple moral structure, which is why it is ok to kill all those countless thousnads on the Death Star.
Totally unrealistic, of course, but that is suspension of disbelief for you... after all, hard to sympatise with the Rebels if they are mass murderers of innocents. So GL made them ALL bad.
In the prequels, it is more difficult... but then who weeps for a battle droid?