Dark Empire has two major problems
THE ART: Google images "Dark Empire Palpatine" and look at the scene of Palps and Luke talking.
Notice anything? It's all mostly two colors, green and black. Although sometimes they use other colors such as purple, pretty much the whole comic is in two colors. Green people, green Star Destroyers. Did you know the E-wing fighters had red stripes on them, as depicted in other sources? I didn't because in the comic they were frickin green. Some people might like this as a stylistic choice, but to me whole pages of green and black just looks ugly.
RESURRECTING PALPATINE/DARK LUKE: One of my pet peeves about the EU is when it makes the actions of the film characters seem insignificant. Usually it's just something like giving a Sith Lord the power to blow up suns, making the ones in the movies (who need a Death Star) seem weak. This comic has some of that, with Palpatine seeming a full on Dark Wizard at times.
But it's worse than that in that it directly undoes the heroes actions from ROTJ. Try watching that scene where Luke declares "I'll never turn to the Dark Side. I am a Jedi, like my father before me." The comic takes away the triumph that scene inspires. The prequel reveal about the Prophecy retroactively makes it worse. Anakin Skywalker's big prophecy-fulfilling redemption was ultimately just causing one of Palpatine's many deaths.
Now that I've gotten those out of the way, here's a smaller Pros and Cons list
-It helped raise Boba Fett from the dead
-Cool designs like the Eclipse and E-wing Fighters and Robot TIES
-Neat ideas, like the Rebels using captured Star Destroyers and the Imperials having a Civil War.
-The World Devastators aren't as bad as latter super weapons would be, instead of being yet another way to blow up a star/planet they're literally giant factories consuming the planet's surface to make more weapons
-This is minor compared to my other problems, but the characters of Salla Zend and Shug Ninx are boring as all hell. Like Lando, they're old criminal friends of Hans' who join the Rebellion/New Republic, but Lando had charisma and personality. There's a reason if you go to their Wookieepedia pages they have few appearances in other works besides one-off lines mentioning them.