Pseudonym IS a name. G+ is an online space. In online spaces, one should use online names.
I want to come to G+ and read posts by Scicurious, Orac, PsiWavefunction, Abel Pharmboy, Bug Girl, Drugmonkey, Dr.Isis, Mike the Mad Biologist, PhysioProf (if his Luddite self even wants to be here), Digby and others. Online, THOSE are their real names.
Whatever strings of letters their parents scribbled on their birth certificates are not more nor less real than their self-given online names. Those strings of letters their parents scribbled on their birth certificates are important to their family, coworkers, neighbors, a few old friends.
But online, it is their Online Handles that have meaning, have power, have voice. I know most of the pseud's "real" names and I don't care about them (for some I'd have to dig deep inside my brain to even remember) - online, this is their personality, this is their real name, and this is how people know them and want to read them.
What about new people just starting out with pseuds? Orac and Revere once posted their first post. So did Coturnix. They built their reputation over time. Many others tried the same and did not succeed (perhaps they were vile and nasty) and nobody remembers them any more.
G+ has an inherent validation system. It is called "Circles". Many people will place (and know how and where to place) Scicurious and Orac in their circles. New pseuds can over time build their own reputations and get included into more and more circles. Nasty pseuds (or true anonymice) will not - they are more likely to get blocked. The system as it is set up in G+ should naturally work well about assigning reputation and trust to those who deserve it.