I can't compare or make any suggestions based on WOW because I'm not a sad loser who sits around on my ever widening behind listening to Scandinavians yelling about.... I don't know, probably how softly the snow crunches under foot.
But I have been playing NWN2 for a... bit, and there are some things that Obsidian could take from that. First I don't care about consoles anymore because of NWN2's way of assigning spells to keys. Since the number of powers increased in Kotor 2 it's logical to assume there would be more in the third... or snots would say.... But I digress, I think assigning powers to keys is brilliant. It's so much easier to press a button and conjure my fiend, than cycling through with the mouse.
I was a little younger than the normal age for Dungeons and Dragons freaks so I missed that in my youth. I remember talk of Bags of Holding, D12's and oddly shaped grey dice that for a four year old was just a pointy thing that looked really wiered, and cool. But the D&D system is the only way really, and Kotor3 if it is made (Don't care much) should draw more from it. But I don't know how multi classing would work for Jedi.... I already said there should be more classes of Jedi, and or branches of the order, such as the Jal Shey, and Makashi, so it could work.
Maybe it would be too complex to change strength in the force to preparing powers for a day, but it could be a way of making the classes different and the game more difficult.