While I won't deny that there were some unfortunate design decisions made in the codebase (some very questionable choices were made at some point), I think that's inevitable in any codebase of a certain size and age that's been worked on by enough people in a company that's changed substantially a number of times.

But that's not the cause of my pain. Bad code can and will be written in Py2, Py3, or any other language. The cause of my pain is that the language developers chose to abandon work on the language that we use in favor of a different language, one that is fundamentally different in some important ways. As a result, the tooling and ecosystem on which we've built our product is slowly stagnating and is getting close to being fully disfunctional.