For KotOR I'm guessing that the only real difference is that instead of turning Bastila back to the light, you can off Malek, take her as an apprentice and get an "All hail Lord Revan" ending cutscene in place of the medal ceremony. Am I right?
As for you not liking it, I dunno... I was hesitant to play it when it first came out, having lost interest in Star Wars after getting burned by the prequels, but I was glad I did, as it managed to recapture everything that was great about the original films. It was also nifty how they were able to incorporate the D&D ruleset into a sci-fi setting. And it's rather important from a historical standpoint as it provided the template for most of the Bioware games that came after. Hell, Mass Effect 1 is pretty much a KoTOR clone in an original setting. And I like KoTOR better because it didn't have the tedium of the Mako exploration and cookie-cutter sidequests. But if you didn't like it, I probably wouldn't recommend the sequel. Like all of Obsidian's other games it's got better dialogue and deeper gameplay mechanics, but it's buggy as hell. And if you thought ME3 had a bad ending.....