It seems like a nice idea. I'm not on board with any new Google platform unless I have some sort of assurance that you're just not going to kill this off in two years, or let it suffer a slow death of neglect and attrition.
Thanks, but you need to grow up a bit, Google.
I've read some horror stories about google pulling the plug on all accounts due to a billing conflict somewhere else in their ecosystem. That, together with the absolute PITA of managing multiple accounts pretty much ensures I will avoid ever paying to put my data in their hands.
But still, this is a very valid point. It's hard to trust any Google service and it's risky to make any significant investment of time structuring your life around them. This is why I don't use Google Music anymore. I invest far too much time into my playlists and music collections to trust them.
Wave was launched to a ton of fan-fare and seemed like a first-order product, similar to Hangouts... which is now also dying a slow death.
For example, they have already removed the marketing page that people here are making fun of: https://imgur.com/a/xsF1ZX3
It is actually quite simple, no revenue no services.