Just actually played this and its not that bad, but it leaves much to be desired.
Okay so here's the lowdown, not much really changes from KOTOR I, but there are some new force powers, a level 3 heal, melee protection and other fun powers! Some force powers were desperatly needed like the level 3 healing power.
Also, this time around your decisions affect everyone, not just your main character. You can push the party's alignment into the dark or light side by your actions. You can guess yourself how to get there :)
A new feature is the ability to breakdown items to create new upgrades or weapons. This is probably one of the best features in the game. This feature becomes important whenever you get your lightsaber, since you can not only add crystals, but different parts to add bonus effects.
However, I will have to say that the exile (main character) becomes ridiculously powerful thanks to prestige classes. These classes make your character ridiculously powerful and able to take on teams of pretty much anything but the really tough enemies. I played Weapon Master and it was insane how fast my character took people out.
Overall the game is good, but the plot needs a little work, it just seems.....weird.
Pros: Adds much needed force powers, breakdown is great for creating new upgrades and weapons, prestige classes are cool.
Cons: Story is weird and ending is just dumb.