If you like looking at those hideous vanilla bodies, maybe. The only time I played completely vanilla was when I first installed the game. It was a looooong while before I came back to it after THAT.
And if I remember right, these do work with the Steam version, you'll just need to fix the timestamps on the Morrowind/Tribunal/Bloodmoon .esms.
I have to agree here. If there is one thing I didnt like, it was those hideous bodies. Even N64 game characters(like Jet Force Gemini) have better bodies than the original MW ones. haha
Aside from the bodies, the original MW has a certain charm to it that warrents your first play through being without mods. The code patch and the MW Script Patch(this is an ingenious thing that isnt mentioned much) and other simple fixes are a great thing to have though.
On thinking of a mod you could probably include on the first time through simply because it makes things more epic, that would be Darknuts greater dwemer ruins. It isnt a simple thing though to run through(like the original), so you might be best off just leaving it.