Having NPCs has many benefits, this being one of them. Plus you can let them do all of the front line fighting while you wait in the back casting spells or using ranged weapons.
I am ignoring the rest of the post in case it has spoilers on the ending. As good as Kotor2? Kotor 2 being a dull and incomplete ending, I would hope that NWN2 is better in that regard.
My ATI X1600XT graphics card starts to lag when there are a lot of animations going on at once, like a lot of people in fights and the worst is when you have a bunch of spell casters casting spells. This is a game that would need a high end card if you want to play with the settings on high for visual effects.
A Gigabyte RAM would be a must have. This game is worse than Oblivion when it comes to keeping the PC high end.
I have not encountered any game killing bugs yet or any bugs for that matter. But I have just reached Neverwinter so I have some more playing time to go.
Setting up all the mines that you have for a trap will help out. That is do it before you talk to her. Force Storm is a good power against those lightsabers.
So far I have Khelgar, Neeshka, and Elanee. They will probably be the three I will mostly stick with in this game. You have a fighter, rogue, healer/offensive spell caster and my character a fighter/mage.
My journey so far.
West Harbor was a good tutorial to start the game off in. It was quick and straight forward way to teach you the basics of the game with the Fair events. My character earned some evil points when the village was being attacked. She didn't like the Mossfeld brothers and decided to slit the throats of two of the brothers.
On my way to Fort Locke I picked up Khelgar a decent fighter and Neeshka, who seems to be a good rogue to have in your party. Did all of the quests in Fort Locke and now I am ready to enter Neverwinter.