Have you heard the expression, "A chain is only as strong as the weakest link?". So adding strong links after a weak link does not "improve" the strength of the chain.
And that is assuming that these new features added are actually sane. From what I have seen, it is not the case. see here [1]
So you cannot improve php with out making it "not php". And I don't think even if the same people started who are working in the language started from scratch, today, it will be much better than Php. Because they are simply not competent (refer [1]), because if you are competent, and has the vision to see the flaws of the language and the community, you won't go anywhere near it. So I think there is zero chance of Php becoming "sane", let alone nice...
[1] https://np.reddit.com/r/PHP/comments/3j88v4/something_about_...