Since it now looks like it really does have a decent chance, and maybe another -1 has a small chance of tipping the balance: my reaction to the proposal is also emotional. Visceral, in fact, to the extent that I'd aim to read and write less Python if it became commonplace.
[Steven D'Aprano firstname.lastname@example.org]
Funnily enough, that's what some people said about decorator syntax, ternary if, type annotations and list comprehensions.
All of them have become great additions to the language.
I hated the idea of aping C and adding += operators and swore I'd never use them. That lasted, well, about a month.
Well - I've come to respect your opinion, so ... OK, I'll give += a try. Frankly, I've grown tired of editing it out of all the packages I download anyway ;-)