Is this on the Level?
Over on the SW:TOR forums today Damion Schubert (one of the Devs) chimed in on a thread about character advancement, leveling, and The Grind.
There are multiple ways to build an advancement system in an MMO. We did indeed choose to go with a level-based system for SW:TOR. It seemed to be the best system to align with our other goals for the game, including the story progression elements. Our version of advancement gives greater returns for questing and story than simply killing critters.
You can read the full post and various responses to it over at the follwoing link: Star Wars: The Old Republic | Community: Forums, Blogs – No… Leveling ? – Page 7 .

For a MMO so built on the crux of “story”, I am glad to see that the rewards are lining up with this focus. It would be so self defeating if mindlessly grinding mobs was required for “certain level ranges” or to finish off “your experience bar” because there is/was not enough quests. It will make leveling less a chore and more a reward for “developing” your character and immersing yourself in the game world. I bet leveling will be one of those things like “oh hey I just dinged and got new x and y” rather then “WHEN THE HECK WILL I GRIND THIS OUT… I NEED X AND Y”. Bravo.