> 1- Separation of powers between rulemakers and judges. In practice many Administrators who have the power to enforce rules and bans are actually editing articles themselves!

There is https://en.wikipedia.org/wiki/Wikipedia:Administrators#Invol...

While admins do have the rights to block users or protect pages, many a times, they leave it to other admins to carry out the administrative actions on the users or pages they are involved with. The editors have recalled or reported admins who had overstepped such boundaries one too many times as well.

And many a time, they'll use mailing lists (even on WP servers, though those mostly are gone now) to coordinate with friendly fellow admins to "take a look at user xyz" and a solid quid pro quo of "and I'll be happy to handle the admin actions you'd like to handle on the pages you like to frequent".