Isn't it already? Pretty sure the official website lists 3.4 as stable.
I work with python and we had no problem using it in production. In fact it's kind of a hassle when I have to dive back in projects that are still 2...mostly because of random encoding errors that happens when someone forgets the 'u' before the string literal or the weird utf8 comment at the top...sigh u.u
I'm not sure but I also believe the error messages in python 3 to be way better. Which speeds up development.
As of library compatibility, not remembering any problem so far. Maybe if one or two (that you need) have compatibility issues, there's probably alternatives to it. Libraries that do not support python 3 tend to get left behind in my opinion.