I definitely don’t want to remove existing behaviour, but that doesn’t mean I cannot be against adding new behaviour to “modernize” a feature I don’t particularly care for. That said, I won’t cry if this gets added (tho if I were a maintainer I might’d). It also adds another non-obvious way of doing what is incredibly simple already, which might confuse people. Although that might just be me. I’m also not a fan of binding the (optional) type system more strongly to the language, even stdlib modules (one should not feel forced to use types).
Anyway, I wish you luck finding a sponsor for the PEP-to-be