I reckon at the minute it will mean less will get done as people will be pissing about changing what other people have said on different waves.
Drag and drop means more file sharing (hurrah, ticket and t shirt sales FTW!)
Bands will be able to host public waves meaning a million requests for guestlist/obscure b-sides/what will you be wearing, leading to 'more fan interaction' which is gay anyway. So that's not the most exciting part about it.
Bands have been able to post mp3's up for the last five decades anyway so that doesnt change much.
What will be best is changing details on gigs when promoters/managers/jesus fucks up and it will be waved right in your face.
I may be missing loads out, will google wave be important in the promotion of new bands? Or does no one care any more about new bands unless your mates are supporting them?
google wave, still not cooler than blackberry, but rad none the less