Yes, pretty much, but that'd have to be combined with some sort of "sharing", "inbox" and/or "following" system like Wave came with. Perhaps email could be hacked into being that, but then we have the issue of "what happens when the service provider goes down" - Drive Realtime doesn't provide automatic saving of the Javascript that I can view and edit my document with, likely ending up relying on a third-party not to go down.

I suspect that it'd be "easy" to build an MVP of what I suggest on top of Google Drive and Google Drive Realtime, or even on top of some of Wave's internals.