I'm a big fan of http://www.uesp.net/wiki/Morrowind:Morrowind, and I know that they have a http://www.uesp.net/wiki/Tes3Mod:Mods about mods, but that section seems limited to a small group of larger mods, most of which have links to their websites rather than to actual wiki entries.

Personally, I'm never satisfied by a readme; and, often a mod with more involved quests could benefit from a http://pluto.fliggerty.com/ or a guide - at least so that someone playing the mod can go back afterwards and see if they missed anything. Even a wiki page dedicated to categorizing and discussing release catalogs from some of our prominent modders like Princess Stomper might be helpful.

If there were a Morrowind Mods wiki, would you post information about your mod, or other mods, in the wiki? Would there be any interest in such a thing?

I would contribute to such a thing, yes. In fact, I'm going to be reviewing "Shrine of Mephala" by Westly fairly soon, and could easily put together a walkthrough for it, if one were needed. I can't be sure yet, since I haven't played it, which is one of the reasons I want to make it my first mod review.

You should talk to http://www.gamesas.com/user/394535-tomlong75210/ about having a section for Morrowind mods on http://tescosi.com/wiki/Main_Page.