About them plot holes, I'm still not convinced an attack on the exhaust port from above would've been all that more suicidal than a trench run. Those proton torpedoes made crazy 90-degree turns on a dime to enter the shaft, so it seems like other approach vectors would've been possible as well.
Also, why didn't Rebels or Imperials alike try to shoot down enemy craft in the trench from above? Good ol' Han didn't play by the rules.
If the Empire brought galactic stability, is the sacrifice of one planet of agent provocateurs a big loss? At what point do the ends justify the means?
-wtk
I don't really have an answer for the "ends justify the means" part, but it seems that when the numbers game is played, it's easy to stop seeing the forest for the trees. Wherever that line is drawn, an empire that would execute a couple billion people as a demonstration of force, in line with their policy of fear, doesn't sound like a "good" empire to me. Also... who would give their ships names like
Accuser,
Executor, and
Tyrant?

While galactic stability should save lives, I'm also looking at the methods used to reach and maintain it. To use a real-world example, North Korea seems relatively stable to me, but I definitely wouldn't want to live there.
P.S. EU aside, those Ewoks were wiped out for sure.