Mivas: But do you remember characters other than two or three persons from the main quest? Do you recall some of their unique lines? Their character's traits? Does solving some quest provides character's growth (not you)?
Fenixp: Specific characters? I don't remember their names for the same reason why I don't remember the lines, but for characters themselves, from the main storyline alone, I remember 5 - that's the Morrowind's storyline alone
to which you can add the characters of Seyda Neen (the first hamlet), that dubious wood elf, that monk-ish guy who 'welcomes' you, that dead tax collector, that guy falling from the sky .....
Then in a larger scope you have at least the 3 great houses, which hold their load of emblematic characters, then there is Umbra as usual .... and then lots of random NPC have a lot of flavor mike the khajiit and argonians slaves.
And at last you have the books. The books in Morrowind have a lot of 'substance'.
Morrowind is a great game, but you have to dive into it and give it a lot of time, which can be problematic nowadays.