I'd somewhat bet the opposite. Geeks will be raving about wave and how it's realtime, XMPP federated, technically impressive etc etc, whilst the average person on the street will have no clue what it does and why they need it.
The average geek is equipped with many methods of communication and collaboration... So of course this just seems like a marginal improvement. The average normal person, though, uses mostly email, and so will find this client exceptionally useful. The average person will just see (perhaps not even explicitly) that it makes it easier to add people to ongoing email conversations, and that it's easy to attach files to the conversation, and that it's easier to branch off sub-conversations, etc.
So how does the average person find out about wave - let alone learn all the terminology, how to use it, etc etc. We're only hearing the geeks feedback so far, because the rest of the world doesn't know/care it exists. I'd be interested if you have some examples of communication forms that geeks didn't start using first - email,sms,twitter, were all pretty geek lead...
I think the average person won't see how this solves any problems they have - facebook,twitter,email,sms all work pretty well for communication.
I can see your point about teams working together - business collaboration - I can see it making some inroads there.
Lots of the things I hear wave does are technically fun, but in practice, horrible design choices - showing text as people type it was the norm 20 years ago. Since then, we've pretty much all agreed it's irritating and not really useful.
Google replaces GMail's plumbing with Wave and the inherent abilities of Wave are introduced as GMail features. Robots, conversation splitting, collaboration, etc.
It's the only sane way to approach it, really.
And I have no idea why people keep harping on live typing. Google announced that there was going to be a way to turn it off about 5 minutes after they pulled the drape off Wave itself.
It's almost certainly a feature destined for the dustbin. As such, it's an utter red herring. Complaining about it is perhaps more pointless than the "it's too complicated" meme.
People probably keep harping on about live typing because it made no sense to include it. It's a gimmick rather than a useful feature.
Also it is too complicated for most people. You can't just ignore arguments and call them a 'meme' :)
Facebook wasn't. Or MySpace. I found out about FB from non-geek friends. I was shocked.
Wave is very open for anyone to make their own clients to use wave in whatever way they see fit. With the right client, Wave could be a much more powerful twitter.
Wave is for solving the key problems with email in a corporate environment:
1) It's hard to track (will presumably offer an API or be trackable by widgets)
2) It's hard to use it to collaborate on a piece of text to be sent out to someone else or included in a document (which is what it's used for half the time...)
3) When adding new people, it's hard to ensure that they have a clear view of the beginning of the conversation - often they get a garbled, over-indented mess in reverse chronological order, that's hard to follow.
4) When adding new people, often they get dropped again if someone replies to all from the wrong email.
5) It's hard to keep multiple conversation branches going. If you're collaborating with 5 people (hardly extraordinary) on a 2-page document, and they each have 1 distinct comment, and each of these comments requires a brief exchange (back and forth 3 times, let's say) before it's sorted out, you'll end up with a fairly messy conversation once it's all flattened out.
6) It's hard to attach files (particularly large or numerous files). And when you add extra people to the conversation, they don't see those files anymore. If there were multiple files sent at different time, sending all of them to the new participant is a pain in the ass.
7) When discussing, say, a document, correcting even a small typo requires a full email instead of being able to just dive in and correct the typo.
There are no doubt more, but this is what I can come up with fresh out of bed.
I don't know if wave will ultimately be compelling enough to draw people away from those other sites and services, but I don't think it will be a complete flop (I'm looking at you, VRML).
I can see instant usefulness to Wave. I have my invite, and one of my colleagues does too. I can't wait for my other cofounders to get access so that we can use it for real work. Email really just sucks in so many ways.
Edit: It's worth adding that a lot of articles and pundits seem to be comparing Wave and, say, Twitter. Wave is nothing like Twitter, nor does it aim to be anything like Twitter. No, we're not going to start using Wave instead of Twitter, Friendfeed, Facebook, etc... because that's not what it's for! Wave might end up being useful for social communications too, but the most important pain points that it resolves are business pains, problems that people encounter when they're trying to work together remotely.