I disagree with integrated private messaging. I think that Google offers these services, and adding redundant services that exist only within the scope of the Google+ boundaries creates LESS centralized management of communications. I think Google's goal is to centralize and consolidate, and it is a goal I think is worth pursuing. I've already got dozens of different ways of communciating - frequently with the same group(s) of people. I don't want one more stream of information to manage. I'd rather have one less.

If a G-mail account is a requirement to have a Google Plus account, then making G-mail the default method for private correspondence between Plus users makes sense. Why have ANOTHER, completely separate method that is still basically e-mail - only e-mail that is is limited to communication only within the Google+ ecosystem?

Likewise if Google Chat is Google's IM solution, why have another IM solution that is unique to Plus? Aren't these extra wheels, that are less robust than the wheels that already exist, that aren't necessary in the first place?

Everything else is spot on, though.