Google Buzz had a lot of import sources available at launch. There was so much noise from automated cross posting that I didn't even know that several of my friends were actively using the service until months later.

In contrast, Google+ is almost completely signal for me right now.

Yes, I was waiting for someone to bring up Buzz. I was also a first-day user of Buzz, and guess what? They allowed third-party import, and very quickly out-of-context Twitter updates overwhelmed my stream. Then there was a backlash, and the smarter people turned them off rather quickly. But the vast majority of people kept on using it. I think Google knows exactly what they are doing here.

Not all the G+ streams are empty, so that dilemma only really has one horn. Bot-posting would raise the noise floor so as to swamp the current (small) signal. Better to attempt growing the signal itself before adding in a bunch of noise that the users will have to sort through.

Now, if one could separate off each user from their bots... that would be neat. Maybe default to only circling a user, but show that they have some bots which one can also subscribe to, if one wants.