As far as I know there is a giant bug list for diablo 2 many pages long, and it's pretty obvious Blizzard is never going to fix any of them as they have been known about them for over 10 years. Fixing many of them would just be fixing typos. I have searched the internet and I can find nothing about anyone making such a mod before.
I would only work for single player because mods don't work online. Does anyone know of such a mod or is there any interest in making such a thing?