I hope everyone learned that breaking compatibility for the sake of fixing syntax (amongst other things) just isn't worth it. I'm happy that Python seems to be finally pulling through this, but a lot of us are still stuck in 2.x land.
I really wish Python 3 had been about concurrency and making it a part of the core of the language. There are over a dozen different python concurrency packages out there and most of them are pretty different from each other. It's confusing as all get out, and we end up religious wars over which one to use.