I'm hard pressed to remember a feature in Wave that does not exist in Docs now. What is it that you miss? I just remember it being dog slow with a lot of latency.
Wave was supposed to be "equal parts conversation and document" (their description). It seems like they separated out the conversation part to Google Talk and made the document part Docs. Wave was kind of the precursor to the state of affairs we have now with Slack and Discord.
