I think it's inevitable that with an adventure that features new discoveries or experiences that there is a good chance of a specialized mechanic, even one that is different than the established core. Most of these are of localized interest and not general applicability. I don't want the campaign/adventure/one-shot writers unnecessarily hemmed in.
You don't want the writers hemmed in? They aren't. Do you not want laws of physics as well in real life or does that hem in your puny creativity? I don't seem to recall the Wright Brothers whining about the laws of physics hemming them in when they made their airplane. Or Euclid, or Newton, or Einstein. They discovered new laws that further refined our knowledge and built upon what came before them. Do that with game rules. Build on what came before you. Further explore concepts, don't just make up a new rule.
I heard this same whiny crap from people writing Star Wars after Disney bought it and destroyed Canon. "Oh no! I have no creativity! I must change everything in order to fit My vision!"
Basically, if you have to break the rules to tell a story, you are not a very good storyteller.
Unless you all want to have a rules mess that needs cleaned up every 10 years or so? Unless you want rules that are not designed to work together? Want rules that are contradictory? Want there to be so many rules scatted in so many places that writers and players and Referees can't possibly know where all of them are printed?
All of this so some writer, who isn't creative enough to figure out a creative solution without having to write new rules, can "not have their creativity hemmed in". That is some serious participation trophy crap right there.
Just like AI Artists. If you aren't a good enough writer to write within the rules, then you are not a good enough writer to write material for an RPG game. Go write a novel or short stories where there are no rules, but don't keep screwing up the rules in an RPG just so a writer of material can feel special. This is why I do not write material for RPGs. I am not a good enough writer to create high enough quality work that works within the rules. So, I don't do it. Same way I do not try and make art professionally. I recognize my limits. Maybe one day I will be good enough, but after 20 years of working to improve, I kind of doubt I will improve much further in these areas, but I do try.