Qt5 is taking the project in some interesting directions regarding the UI aspects. I think it'll be a good thing overall but it's certainly proving a bit contenious amongst people who're comfortable with QWidget and don't like the idea of JavaScript being a first class citizen. As long as it's as fast I'm happy.
I think there's nothing to fear. The announcement states that in most cases you should be able to port your applications from Qt4 into Qt5 with little or no modifications.
On the other hand, I was an skeptic in regards to QML at first, but after using it I fell in love with it. It's logical and very easy to learn, and having similarities with web development means expanding the availabilty of programmers and designers who can work immediately in your project. Great stuff.
As c++ programmer,you have to use some(in most cases,a lot of) java script to accomplish your job, I guess that's why C++ programmers complain about it.
JS should be an option, without it QML can works fine, but in the real situation C++ is optional. It is hard to keep the balance.
