Well, actually, Raymond was proposing an alternative to Py2's special __metaclass__ attribute assignment syntax, which honestly _is_ an abomination (and the big part of reason why that was changed in Py3 to a keyword argument in a class definition).

And Guido missed the point that in frameworks such as Django, the inheritance is the main thing people want, metaclasses just being a technical implementation detail (the easiest proof is that with modern descriptors with __set_name__ and ordered class namespaces, it's unnecessary to use metaclasses in Django model implementation at all). Here it is exactly the opposite.

As I said in the linked comment, I think we missed the opportunity to make Python much more powerful, practically shunning the idea of keyword arguments in a class definition totally. But as it is said, Guido's will  be done. :-) Thanks for the link.