The development server seems like the only good thing about it.
Traits looks like a silly implementation of multiple inheritance mixins, with a 'use' keyword that doesn't really fit in with the language itself. And the whole 'insteadof' thing looks weird. It will lead to hackish code for many people, encouraging weird monkey-patching.
The author says "when stored in an array", then proceeds to use "$functions['anonymous']". That's not an array. Sigh. I know PHP likes to call them that, but I just find it weird that they would continue to insist on mis-naming two of the fundamental data types of computer science.
The introduction of closures can only be a good thing, and a lot better than the passing of a string name of a function as a callback argument from before.
As usual though, it's expected that most servers and frameworks won't get the update for some time, due to whatever backwards incompatible changes have been made.
I know it's all the rage to hate on PHP these days, but even giving an objective look at the state of the language, given the thriving ecosystems of its competitors, makes it look to me like something I would never touch.