I actually agree with this. And I like your second point around LOC as a yellow-flag around poor domain understanding.

I tried to acknowledge the deficiencies in LOC in the second paragraph... but it felt like a useful shorthand for conveying a sense of scale and complexity (at least to an order-of-magnitude) in a domain-agnostic way.

Outside of Mypy, we use: black, isort, flake8, docformatter, and autoflake (to remove unused imports) -- all on pre-commit + enforced on CI. I'd like to see Black cannibalize more of that toolchain :)