I've read a bunch of hype about the Google Wave presentation and then actually watched the hour+ long presentation that the Google Wave team gave. Here's some thoughts on the matter.
Is this truly the revolutionary architecture they are hyping? It could be, but only if people buy into it and it does not wind up being too complicated to understand. Thus, its success depends on how well it is hyped, how well they can manage the early-adopted/tech crowd and if they can have enough stuff built on top of it for the average person to get some uptake. Given that, the early developer preview demo and release makes a lot of sense.
The basic fact is that they have the right idea: email is archaic, IM is archaic, and there are all these emerging new interaction patterns: Twitter, Facebook, blogs, etc. Can't we put all these things under one roof? My answer is: maybe. If you design something too general, it fails for being too complex/abstract to comprehend. I wonder if the generality of Google Wave may suffer from trying to be too general.
In some sense, you could give a demo of the TCP/IP stack today and woo the crowd with all the things you could do with it: email, IM, blogs, facebook, twitter, etc. Wow, this thing is amazing!
So is it something the user cares about or something only developers care about? I think it is too complex/abstract for the end-user to consider or care about. But maybe we sit in a time where something as general as TCP/IP is needed, only one level up, and maybe this fits the bill. There's no question that building apps today is a royal pain in the butt, especially handling concurrent events and all that makes up implementing the more collaborative things. If Google Wave winds up being the API that makes all this easier for the developer, maybe it will get uptake and be the "next big thing".