The repetitive dialogue does get old fast. But the books are great - there are many interesting and funny stories to read, and these help flesh out the world more than talking to the NPCs.
What I thought was really nice about Morrowind was the vast amount of pure exploration that is possible. There are so many interesting places to explore.. Many have nothing to do with the main storyline and have an air of mystery about them. Sometimes (but not always) there is a nice piece of loot to be found.
The world builders did an amazing job with Morrowind, and the quality of their work makes the game worth playing.. provided you have a high end system that can do it justice, or you don't mind a bit of choppiness. (Not all gamers demand high framerates.)