You're meant to use the hangouts app, or the hangouts homepage.
So... frankly, that's likely to be the end of G+ as a standard tab for me. I get my hangouts within gmail, but somehow it's a bit nicer in G+ - but G+ without hangouts is unlikely to hold enough interest.
Nice experiment google. Pity you ruined it.
You coulda been a contender
G+ remains a standard tab due to the sum of a few factors - regularly interesting links from people I follow, and hangouts. Either alone would not be enough.
I don't think I've ever used (or noticed anyway?) events in G+