I'm about halfway through KOTOR 2 when I made these suggestions, keep that in mind please...
1. Both Revan and The Exile in the game. One on the Light Side, the other on the Dark. And you can pick which one you play as... just a thought.
2. Definatley more interaction with NPCs, and more interaction between them.
3. XBOX LIVE... somehow.
4. Make it more of an action game (a 'Halo'-like 'Jedi Accademy' game)
5. Definatley needs a new graphical engine. AND fighting engine, because if it wasn't for the storyline and characters, the games would be boring, in my opinion.
6. More faces for your character you create... who here has SEEN the astronomical number of options for faces in the 'Create a wreastler' modes for wreastling games? It's insaine.
7. Play as an Alien race, not just human.
8. Of course, take advantage of XBox Next's huge number of features (it's not just going to be more powerful, of course).
9. Think of the possibilites of the XBox headset, the kinds of commands you could order... if only acouple short responses ("Yes," "No,")
That's all I can think of, but I'm sure BIOWARE has ideas ten times better than that, cuz the know exactly what they're doing.