My major problem has been the documentation of the project and how top contributors are unable to accept how bad it is. Discussions about improvements and attempts at improving it at regularly shut down or impeded. Coming back to the “harsh defense of perceived territory”, it distinctly feels like existing teams are supposed to be the only ones making changes to the things they own. Contributions from “outsiders” never exit nix review hell and are nitpicked to death.
I made a one time contribution to the nix docs, I also got the impression that managing documentation could be better but it did got accepted after a few changes.
With that said there are alternative projects that provide a form of documentation to nix.