I think a TRUE free software distro must provide easy-to-use tools to fork, modify, replace, and share "system" or "official" software packages.
Even though some distros are open source, but it is hard for a fork to get into the main repository. Forks usually don't have a place for shining. Any package in your system should behave like a git repo: you can branch it easily, and your system still works (providing that your code is correct). When update, your branch stays still.
Debian provides src package to build locally, but it doesn't work very well, because Debian src pkg usually old, and you cannot easily share it efficiently. So, A distro that supports easy forking must update frequently to make sure everything is new without many distro-specific modifications. There should also be a hub to collect all kinds of forks and show statistics about them (like popularity).
The system's base/meta package must have very minimum dependencies so that if you dislike a component, you can choose any alternatives (such as using Y-windows-system to replace Xorg, rust-based utilities to replace GNU core utilities).
There shouldn't be one large official-approved repo at all (the core repo should be absolute essentials only). For all packages, several forks/alternatives should be able to exist in parallel (even though people will stick to the most famous ones amount alternative packages).
Why?
Even though free software is open source, you still have constraints. The original author(s) control the domain name, the .git repo, and the bugtracker. If he or she is a tyrant, you will lose some freedom. They may add features that only for their own need or against half of the community. A fork would usually cost a lot. For example, due to the control of GNOME-SHIT-FOUNDATION, GTK keeps removing useful feathers and getting harder and harder for developers to writing actually useful software. We need a distro that uses GTK that doesn't come from GNOME to enable from a great fork from GNOME. This is hard, but if distro respect forks equally like the ones from "main repo", it would be easy.
tl;dr -> The governance mdoel of Arch (and Gentoo) actually makes a lot of sense.
However, I don't change my mind that users who think they are smart by using arch are stupid. I still think some of the arch's "philosophy" is anti-humanity.