Actually I think "mediocre" might be too much praise for it.
First off, it's buggy. It's *really* buggy. It's buggy to the point where the characters sometimes blatantly disobey your commands. It's buggy to the point where the ingame text is flat-out wrong. It's buggy to the point where going into stealth mode made my character start rollerskating. I'm not joking - it refused to play the "walk" animation, and so I just slid everywhere. If it was a PC game, I'd be saying "oh well, I'll just wait for the patch". It isn't. There is no patch. It will always be this buggy, until the end of time.
Second, it's linear. Painfully linear. The quests are obvious (and to be honest, I can't think of any yet that haven't been "go bring me this item", except for the one that was "I could really use some rakghoul serum. Yep, Really could. I'm not going to ask you to get some. But I could really use some.") The plotline is . . . cliche. I can't think of a better word. I mean, it's not cliche in that it's mildly different from the cliche. But it's utterly uninteresting. Prediction: I find part, I beat minigame, I find commander, commander sends me on missions to other planets that will hopefully be slightly more interesting.
None of this is helped by the fact that I deeply loathe the D&D system. I flat-out hate how leveling works. It's almost as bad as Rifts, but at least Rifts has some imagination to accompany its lousy game mechanics.
And the final problem that just makes me wince every time I think about it -
You know how RPG games have conversation trees? The other person says something, you have a choice, they respond? Well, KotOR has come up with a brilliant new strategy - conversation lines. The other person says something. You have a choice of three options - but it doesn't matter which one you choose, because the reply will be the same. It'll be something brilliantly crafted so that whatever you can choose to say will apply, of course (for example: "These Jedi rocked! Then they betrayed me." "It must suck to be betrayed by your commander/It must suck to be betrayed by Jedi/Was that really the most painful part?" "No, it's not like that . . . It was that my friends went with them!" Yeah, thanks for giving me a choice, guys. OH WAIT YOU DIDN'T (my mistake)).
I noticed it for the first time when I reloaded a game to try a conversation again, picked a different option, and got the exact same sound sample - now it's just glaringly obvious every time they do it.
Oh, yeah, speaking of sound samples: So you've got humans, right? And they talk. Voice samples. All well and good. And you've got aliens, right? And they talk also! Only 'cause they're aliens, they don't speak English. They do other things. Like, alien noises. And Wookiees grunt. Only, see, it's not English, right? So they don't need a unique sound for every single line of dialog. So - surprise! - they didn't bother to provide one. End result: I'm talking with a Wookiee, and he uses the exact same sound sample for three dialog lines in a row.
That's one mighty versatile language of theirs!
I give up. I don't see why people like Bioware. Baldur's Gate was okay, with a mediocre battle system. Neverwinter Nights was okay, with a mediocre battle system and (I'm told) a painfully obtuse editor. KotOR is taking a step back, because there's no editor. Now it's just okay, with a mediocre battle system, and this time you have ranged weapons with unlimited ammo that are basically as strong as close-combat weapons, so all the combat is blisteringly easy.
And people love this company why?