I think Google did incorporate a lot of this functionality into Docs - multiple users editing the same doc at once is pretty close to the functionality I wanted from Wave, and I've used it multiple times to great effect.
Agreed that the collaborative editing from Docs is great, but I believe Docs already had that functionality before Wave.
The kinds of things I was thinking of is that there aren't any "subsections" in docs (comparable to Wave's replies); and Docs still isn't a "container" in the way that Wave was -- you can't embed a poll, for example.
