G+ doesn't really need propping up, most of the people I enjoy reading are on it, I get more engagement than I ever did on Twitter or FB with the people I'm interested in (note, not friends, but interests), and with a less infuriating comment system. I'd personally rather not have G+ turn into FB.
In fact, I take back my first sentence, now that I think about it, I'm somewhat fearful of YouTube adopting G+ comments, because rather than improving the civility and intelligence of YouTube's comment audience, it might destroy the civility and intelligence of the G+ community.
One could argue two ways here. On one hand I think it's actually interesting and instructive to read comments from anonymous sources - what people "really" think, without the filter of being tied to their real identity. On the other hand, there are countless examples of people proudly posting/tweeting/etc horribly sexist, racist, insulting, and idiotic things under their real names along with a profile picture of themselves, so it's not so clear that removing anonymity will transform the comments section into a particularly erudite and informative place.