Oh, ho, ho. You want me to explain how KotoR 2 sucked? Alright, let's get started.
One: Peragus was incredibly long and tedious. It overstayed its welcome by a truly remarkable amount. I haven't seen that many grey corridors in a -long- time.
Two: The party members have three types, with a little overlap between them: One note characters like Handmaiden and Visas, and annoying sacks of shit like Atton and Kreia. The only good new character was Mira and even then only because she has a few funny quips. The third group consists of Mandalore, HK-47, and T3-M4. You know what they had in common? They aren't Obsidian characters.
Three: Kreia spends the entire game bagging on about how awesome Revan is. The game essentially tries to suck your dick. Somehow, I found this very obnoxious.
Four: Nothing you ever say or do will ever please Kreia and/or make her shut up. There are a couple points in the game where you're presented with a false binary choice so that Kreia has an excuse to monologue about how you're a failure. The beggar on Nar Shaddaa comes to mind - if you give him credits, you're a failure because he'll just get mugged and killed right after. If you don't give him credits and shout at him, he'll run away crying and then murder somebody. If you walk away and don't make eye contact, you...oh, wait, that option isn't available. And somehow, I don't like being monologued at for how much I suck. Especially when at the same time the same woman is trying to fellate KotoR 1-playing me.
Five: This is the game that introduced the Influence system, a bane of roleplaying if I ever saw one. I mean, I thought karma systems were bad, here you have to jump through hoops to make sure your characters like you or you don't get see half their mediocre stories. And I swear, this thing goes up and down like a hooker's knickers for no readily apparent reason sometimes.
Six: Why can't I stuff Kreia in the airlock and flush her out into space?
Neverwinter Nights 2's sins are far graver.
One: Oh my God, the ending. Rocks fall and everyone dies, are you -shitting me-?
Two: You're really going to make me work with the asshole who killed my favorite party member? The guy is a -warlock- the most useless class that exists.
Three: Oh my God, what the hell is up with the toolset? Why is Neverwinter Nights 2 multiplayer less popular than Neverwinter Nights multiplayer even -now-, this many years after release? Oh that's right, because NWN2's toolset -sucks ass-.