Sounds conceptually like an Acrobat portfolio-Or Autodesks Sheet Set Manager for AutoCAD
On the one hand it could be good to have another heirarchal level to kind of hang things off of-especially if it presented itself as a drawing Tree. It might make preparing a tech-data package a lot simpler.
Couple problems I forsee:
1) reference management becomes more complex: To rename a drawing, you now have all of the same considerations that you do renaming a model.
2) file management becomes more complex. You now have all of the same headaches of missing references that you do with assemblies
3) OK, in my industry and the last three companies where I've worked, the top-level assembly with a BOM is about as top-down as a product gets. All of the other master informat like routers, work insturctions and stuff like that is managed in the ERP system. When you introduce a file type that doesn't have an analog document type in your organization, your bound to have one inadvertantly constrain the other. This is one of the reasons Sheet Set manager doesn't get used too often
Still, I like the idea. As with most new tools in Solidworks, it's success or failure would be determined by how well it's integrated with the rest of the solidworks functionality.