Not liking the bug tracker and mailing lists as well as several other points come across as typical things-need-to-be-done-differently now, which has destroyed the culture and meaningful participation in other projects, like Python.
I'm sure there are many valid criticisms of Debian, the main one for me is overpatching upstream packages.
Getting in a patch fight with a .deb maintainer is a right of passage that everyone in the OSS world gets to go through. The slicing and dicing that is done to well mannered software that didn't harm anyone is atrocious. PETP (People for the Ethical Treatment of Packages)
Distros and packaging have much lower relevance as operating systems are viewed as applications, rarely are unix systems multiuser, often serving a single software package. Even desktop operating systems are getting containerized, Qubes, etc.
The bug tracker is objectively awful. It takes 15+ minutes to subscribe to a bug, which is ridiculous! Absolutely no one would write a bug tracker today where everything is processed by email[1].
[1] Which is not to say that messaging is bad - a web interface with a proper message queue behind it would be fine. In fact that's how Fedora's systems work. It's that email is not a reasonable messaging system for this purpose.
Tell me about it. Doing bulk updates to dozens of bugs as a routine daily activity was an exercise in masochism. As for making comments on existing bugs, you had to manually download the mbox archive just to make sure the right recipients were copied in.
It was pretty neat in 1998. Today, it's long eclipsed by pretty much everything else.
If I were Debian, I'd migrate the whole lot over to GitLab issues seeing as they have the infrastructure for it set up (salsa). The problem is there is a very vocal minority who still think it's not only good, but the best choice for Debian. I doubt the silent majority who suffer it agree. Like anything, it's an entrenched part of Debian culture that's hard to change. But it was time to retire it over a decade back.
I'm sure there are many valid criticisms of Debian, the main one for me is overpatching upstream packages.