Maybe the reason it doesn't have "heart" compaired to their previous game was because we already had so much background (in KOTOR) to start with, so you were more vested versus Jade.
I think it is just a dull story and bad writing. I was definitely vested in Baulders Gate and BG II, both original games from Bioware. Neverwinter was a good engine, but boring writing, much like Jade it seems. Neverwinter's expansion was very good though (second expansion). KOTOR also seemed to have a pretty good story line and system, and it did have the familiarity you've expressed.
Jade just really falls flat to me. I've tried a couple times, and I just can't get into the game at all. I dislike the combat, and there is nothing else to keep me going. The decisions, as mentioned, are all obvious and generic, and seem to have little effect anyway.
Even though I didn't like Neverwinter's story, I at least enjoyed it. Jade Empire is the first Bioware game I just don't like, and can't get into at all. I think it may be one of my biggest disappointments in year, as I thought I'd love it.