Many people are crowing about how Google+ has revolutionized social communication and sharing. But I don't see it.
One thing Google+ does well: privacy
Google+ does allow you to keep something private if you want to. Something like "I'm so glad to be on vacation this week," is a very natural thing to post, but I don't really want to broadcast that I'm out of town to everyone I went to high school with (and their friends when they comment on my post). Sharing with a limited group and disabling re-sharing is a welcome innovation and it's something that Google+ definitely does better than Facebook or Twitter.
One thing Google+ tries to solve but doesn't quite: broadcasting
Google+ tries to integrate Twitter-style following (a broadcast/subscribe model) with Facebook-style friending (a sharing/stream model). This is admirable, but the broadcast/subscribe model only works if people share things publicly. Combine this with the fact that Google+ is encouraging us to share selectively, not publicly, and it means that the follow model is just not that useful in Google+. If you want to communicate with someone, the relationship should be reciprocal, because if they don't add you to one of their circles, then they won't share anything with you, and if you don't add them to a circle, you'll never see anything from them in your stream.
It's interesting that even though reciprocal relationships are the only ones that matter, Google+ de-emphasizes them. It does a few things to help you follow people back when they follow you, but not nearly to the degree that Facebook does.
Google+ ruins: serendipitous discovery
Google+ is encouraging us to put people into their circles and only share things with those for whom it would be relevant. But if I add someone as a friend on Facebook because they're interested in voting systems, sometimes it's great to see their posts that are not related to voting systems. A post like, "Just completed the longest bike ride of my life," can help me connect with someone and find out if we have more shared hobbies or interests. But whether or not I'll see that post is not up to me and what circle I put the sharer in, but up to the sharer and what circle they put me in.
Another example would be someone who knows that they have different political opinions than I do and puts me in a circle so I won't receive any of their political posts. But I like to receive well-thought-out opinions from people on all sides of the political spectrum. As long as people are thinking for themselves, tune me in!
Now, I definitely don't want to know ALL the personal details of everyone's life. And if they want to keep something private, I can certainly respect that. But I am definitely interested in big accomplishments and thoughtful opinions of people I used to know or may not know very well yet. Google+ doesn't really make that discovery possible.
The big problem that Google+ still does not solve: Too much noise in the stream
Some people have the opposite problem. They wish there were less information in their news streams. Part of the hype around Google+ is that it can help solve this problem.
But with Google+, if you put even one person in your circles who thinks they are a broadcaster, then they're going to share everything publicly and they're going to fill up your stream with things you're not interested in. Even friends who aren't "broadcasters" might put you in their most personal circle and choose to share too much information with you and there's nothing you can do about it except remove them from all your circles.
What would be revolutionary: Tagging done by the sharer, filtering done by the receiver!
Why should the sharers have complete control of what shows up in my stream? If they have something that they're willing to share, why not let me decide what is the right balance between too much and too little for me?
The "share with" prompt should be replaced with a "tag" prompt and we should be encouraging people to add relevant tags to their posts. In many cases, the tags you should choose would be very similar to the circles you would choose now. Friends could suggest tags if the author didn't select any.
Then the recipient could filter out all political posts by some people, or give priority to all technology posts by other people. Or not to show anything related to Ultimate Frisbee unless two other friends liked the post. There are certainly many other valuable filters that could be created. But the bottom line is that I should have control of what shows up in my feed instead of everyone else.