I had the same reaction to the demo. I had a hard time playing D:OS2, stressed out with having to play / party with a bunch evil characters (with the exception of Lohse, who's merely possessed).
Larian does a good job of making all of the companions interesting. But Minsc, Jaheira, Imoen, and Haer'Dalis were interesting too, without being evil. And maybe Keldorn is simple, but there's still something epic or at least nostalgic about striking that fantasy trope of the paladin (or the ranger or warrior, etc.) dead on.
