I think that the problem is not the personalisation but all the stuff they had to build to make it happen, the side effects of prioritising Google+.

I don't mind a functionality that I can disable, the real issue is all the stuff I need to go through to have that functionality that turns out... I don't need or want!

So Hangouts will provide some advantages over XMPP, at a cost. It doesn't matter I don't really need/want the improvement if I can't keep using the stuff that was already useful to me.