One aspect may be that people just aren't that satisfied with some of the design decisions of Python. In this case the (perceived) issue is probably unnecessary verbosity in declaring classes, which I agree with. Due to the lack of macros changes are made through decorators and other metaprogramming magic, which brings about some collateral issues.

I find it preferable that such changes are possible outside the central committee bureaucracy. You really don't want to end up like C++ w.r.t language evolution.