What I'm getting from the discussion is G+'s intent is to create a sitewide community standard, based on an old principle to the internet. When e-mail and bulletin boards were a new thing on the new internet, people said a lot of things -- a lot of things that moderators were sure that they wouldn't say using their own names.
I'm sure that's reaching in some cases, based on what I've heard in RL human spaces, but to an extent there was a point. Many people wouldn't have been as rude if they had known that they're employer might be reading and could link it to them. So it seems to me that G+ aim is pushing that community standard of politeness, except they are trying to extend it sitewide.
This doesn't serve fannish interests and ignores more than a decade of internet reality. The fannish community standard of communication is very different than the general public standard. I mean we put up a post and say we want to talk about graphic sex, toss up a cut tag and politeness has been observed. In that way our community is self-regulating. For good or bad we have plenty of mechanisms for regulating conversations within the community, even if it means subdividing into specialized groups. All the varied internet communities have done the same.
Journal Sites (LJ, Dreamwidth and the clones) wer really a proto-social networking site. I remember the fannish bristling years ago when LJ self-identified as a social networking platform. We as users saw a substantial difference between communication on LJ verses MySpace and Facebook. And while there is a substantial difference in the way we communicate, I don't think anyone doubts that LJ is a form of social networking nowadays.
The big difference? Ease of sharing information. Facebook automates sharing details - it tells anyone I've ever chatted with that yesterday I said I liked NCIS and wanted to read the feed from Buy.Com. It has one button ability to let people that watch me know that I've been chatting about some interest that people didn't know I had.
In contrast in LJ, I can join a comm about corgi breeding and no one on my f-list would know about it unless they chose to cruise my profile and look up my comms. Or, you know, I chose to tell everyone about it. I haven't played with it in a while, but I believe we can also hide our comm list, so on LJ I could indulge my fannish and corgi interests and neither community would have to know about the other.
And when that was not enough separation, it's no big deal on LJ to create multiple pseuds to indulge in divergent interests.
G+ is not just trying to create a community standard. They are trying to create a site-wide community, based on the idea that people are more polite when they are using their real names. How successful executing this concept will be, including verifying people are using their real names, is yet to be seen and you can place your bets.
Based on this, I find it difficult to see a way that fandom could create an independent fiefdom, like we have on LJ and Dreamwidth