I was mostly thinking about action (or generally keyboard walking) games but that's good to know, I never got to play those titles honestly.
It's not like customizable difficulty would be mandatory - you have your default presets and an option to customize. You could even add a disclaimer about how "modifying difficulty can break the experience" or whatever.
I'd rather have a choice and not use it than be stuck with options that never feel "right".
I realize that games (and software in general) today are about simplifying things and removing any possibility of user messing up but it can make the end product way less engaging in my opinion.