It makes a significant portion of TOR. It may not be as good as a proper RPG, but without it I doubt I would have even tried this game. I had a fervent dislike of MMOs.
Then you are a rarity among MMO players. As most wouldn't stay just for the storyline, especially one section that's 10minutes in length. Though admittedly, I don't know how that account for the majority of TOR, or do you mean just for you, it's a significant portion of TOR?