Are you counting the unofficial patch, and the sort of semi-official plug-ins?
Nope. Vanilla is still good, but if you can fix the glaring bugs that were never patched...why would you?
Technically I play the xbox version once in a while, which is pure vanilla. but otherwise it's just code patch and graphics extender. never had the time to explore gameplay mods...
I only started playing Morrowind last December. So I don't think I've had time to get sick of vanilla Morrowind yet. I only use one mod, Galsiah's Character Development.
By the way, here's a thread you might be interested in reading: http://www.gamesas.com/topic/1450317-still-playing-vanilla/