I'm not sure you really understand what you're asking for. The project you are describing would probably take YEARS. Aside from the modifications to the scripts and NPCs, you would have to create/import/modify meshes and textures for every item, weapon, armor, NPCs, creatures, the terrain, etc. Let's face it, while Diablo 2 was and is a fantastic game, but realistically you should just wait for Tamriel Rebuilt, Skyrim Home of the Nords, Project Cyrodiil, The Orsinium Project, and many other amazing groundbreaking mods that our community is currently developing to come to their fruition.