I personally have never been a huge fan of multiplayer, but it's extremely popular, I wonder why they stopped. It could have really helped the game's popularity and sales, I imagine.
I'm really interested in integrating the DLC into the main campaign, with the Tatooine and Hoth ones being Dark side only, of course. Looking through the files, I imagine it may be possible, assuming we're able to recompress the files eventually. The biggest problem may just be the placement of the Jedi Temple level, and how to fit it with the cutscenes!