The Hivemind GitHub is pretty active, with commits on a nearly daily basis. The project is much more than just Communities - a comprehensive social platform (interpretive) layer on top of the Steem blockchain. From what I can tell, there's just one developer assigned to it, at least externally, which is why it's taking so long. (I wouldn't be surprised if there are other developers testing it internally.) They are doing a great job, though, but I do hope to see more developers actively work on it. As others have pointed out, it was mentioned in last week's update too.
But yes, I appreciate the general sentiment. Hivemind is all I care about. It is abundantly clear that the number one complaint for lot of newbies is "discoverability" (well, apart from being butthurt about their earnings, and the bandwidth errors), and many would be excited to know more about Communities. A dedicated post about it is very necessary, outlining the final specification, as well as answering the big questions like "Who owns the community namespaces?"
Indeed, been wondering the "Who owns the community namespaces?" question last week after the winter update. For example who will own the big ones like travel, nature, sports, .... ? Is it first come, first served? Will there be voting, ....?
And what with the smaller niches. I follow the diving tag daily and wonder who will be given the possibility to make a diving community and appoint the moderators and what will happen when the owner of a community drops dead or leaves the steem platform?