I think you're correct - but I think that almost everyone is missing the point and just talking about the client. The current Google supplied client is optional, and will change. What's more, other clients will emerge that do different things, are simpler, more complex or just different. You could - and I'm sure someone probably will - write email-like clients, or even IMAP-Wave gateways which enable you to use Outlook/Evolution/Whatever and participate in waves via traditional email paradigms. Clients that looks like twitter, pidgin backends (hey - it's just XMPP, this is probably already there), clients that just lifeblog everything you do into your personal life-stream wave (tsunami?)
Wave is a platform. It would be pretty amazing if that platforms killer app. happened to also be the very first client anyone wrote for it. I would imagine that a lot of conversation like interactions that we now have by other means - placing orders, technical support, supply chain management, etc... will become waves, but I don't know what will be the killer app.
Unless every client is just as free-form and chaotic as Google Wave, each kind of client will have a different community and a different communications style. There's not much to get excited about until one of those yet-to-be-invented (and presumably more structured, less free-form) paradigms actually emerges and catches on.
