Actually, there is a way to have 1 project = multiple files. I personally was not aware of how to do this since STEP as adopted by IFC doesn't allow the referencing of other IFC files in the same way that code can link together.
However, John Mitchell tells me that it is possible and the way bS endorses right now is match GUIDs, and then the ownerhistory dictates whose IFC file contains the actual content. For example, you can have one file which only contains project prepared by the client, the surveyor inherits project and specifies site in his own file, then the architect inherits site and specifies building and stories in his own file and so on.
Having an actual element simply makes the UI consistent with other spatial containers which are already elements. Also, I guess sometimes you want a project library, not a project. How should we support project library?
As for attributes, yes, project doesn't have that many attributes but the most important attribute it does have is the map conversion to specify coordinates. (I hear it might move to IFC site in the future though which makes more sense). At the very least, if project isn't an element, I'd like to implement coordinates mapping if you're ok with that