Honestly, I get the idea of wanting to tidy up the place. But separating everything into minimal categories like this is just going to get more messy.
I do like the idea of separating mods for a cleaner experience though. As mentioned above, maybe having:
1. Mesh Mods
2. Hair, Faces & Poses (Perhaps combine this one with #1, depending on what other users think?)
3. Stages
4. Voices & Songs
5. Oldschool Texture Modding (uMod)