Justin Alexander has a good article on why GMs shouldn’t fudge rules and die rolls — https://thealexandrian.net/wordpress/43708/roleplaying-games/gm-dont-list-9-fudging. He doesn’t mention that fudging subtly corrupts you, giving you a sordid aura and making you more likely to do murders, but I presume we all know that by now.
Alexander also has a has a plausible conjecture for why most realm/business/tavern management etc subsystems fail — because they tend to be closed systems, rather than integrating naturally with the main loop of the game — https://twitter.com/hexcrawl/status/1185260871062183936?s=09
Finally, Patrick Stuart has been looking at the OSR-space and has concluded that BX/Moldvay D&D is the common language that makes most of it work — http://falsemachine.blogspot.com/2019/11/the-bx-commons.html. This aligns with my experience — I see reddit and blog posts by people playing OD&D, but they’re rarely the people who are writing things I’m interested in. And I don’t see much about Holmes, Mentzer or AD&D at all.