I have to say that I was pleasantly surprised by some of the new language features that php has borrowed from elsewhere... eg: closures, anonymous functions, docstrings.
IMHO php is held back primarily by messy, inconsistent documentation and extremely ugly parts of the core library that are also riddled with inconsistencies that should have been deprecated years ago.
Not that I would consider starting a new project in php - I just love programming too much for that; but I believe php will evolve, benefiting from other languages.
Really, it needs it's own "Python 3" (out with the old, smarten up the new).
I agree that they should take things even further and really clean up the language before releasing the next major version. Fix the needle-haystack vs. haystack-needle inconsistencies, function naming conventions, and so forth.
The adoption rate of a new major version on shared hosting providers is relatively slow, so it'd be a perfect time to really shake things up and clean it up.
But we are missing the point here. PHP could need a cleanup from the ground up even if they have to break a lot of stuff this could help the language to evolve.
Don't bet on it. It has been too many a years already, and no dice (or minimal dice)
Having listened to several Python core developers as well as core developers of some major web frameworks and libraries, I have no doubt that Python 3 will replace Python 2.
I think the key tipping point will be when the major web frameworks support it.
The official party line on the delay was the lack of a WSGI spec for P3, but there has already been one for several months now.