No rule is inviolate
Reminds me of things like Power Attack from 3.5/Pathfinder. It was a "mandatory" feat, and there should be no such thing.....Then resulted in all Fighters needing to also have it or they would 'suck in comparison'....
I don't use multiclass because it doesn't work like it did in AD&D and leads to goofball abuses and "builds" people find on the internet. Games run perfectly fine.
I still keep feats, but it's starting to feel like an older edition. There's 1/2 that no one will ever take, ever, and others that are mandatory for a particular "build." I've yet to come up with a fix that would suit me, but haven't tried a game without them (yet).