I agree that G+ needs to do a better job of integrating other platforms, however I believe that it's a matter of preference rather then someone doing something better. I choose to blog from blogger, I tried other platforms, didn't like them as much, so I stuck with Blogger.
But yeah, I use Tumblr a little here and there as well because it's nice to not be stuck to 140 characters. But like I said, it's a preference type of thing. For what it's worth I spend more time here then other platforms.