I am ambivalent about removing these three. Technically speaking, it is an API change (although a very far removed edge case of someone using those three arguments as positional arguments). I don't really see any benefits in changing this part.

The main idea of the kwargs, IIRC, was to be a catch-all for artist properties, not for axes properties (although I think "label" is an artist property...). So folding xscale and yscale into kwargs seems "wrong" to me.