Even with the restoration mod the ending still feels incomplete, probably because it is. There's only so much modders can do or else you risk venturing into "fanfiction" territory. Still, I thought the team did an admirable job considering the material they had available.
During her final speech Kreia does a little info dump about what's going to happen to the Exile's companions, except the droids and Bao-Dur. I think you can even decide if the Exile is going to look for Revan. I recommend you read this excellent Let's Play
, specially the last chapter
. It also could have something to do with you going Sith, I've read that a dark side playthrough isn't as fulfilling as its counterpart.
KOTOR 2 is a great game, but you need to keep in mind its flaws. If only LucasArts didn't rush Obsidian...