FrogReaver
The most respectful and polite poster ever
If a rule is interfering or impeding roleplay (as in the case of your scenario) then the DM should change the rule. It doesn't make sense one player is playing the macho, brawny fighter and the other is playing the scrawny weirdo sorcerer, and the beer drinking, fist throwing, bar room brawling fighter should not be trying to intimidate people because the rules say the high charisma sorcerer gets a better die roll. Everyone should do what they want to do, but that doesn't even make sense when you think about how this would play if it was a scene in a movie. That was a rule which clearly wasn't thought through.
I think too many see high or low bonuses and take that to mean some character is better at something than another. In a typical session intimidation is likely to come up relatively few times. It's conceivable that the fighter with 8 charisma could roll high on every one of those checks and the sorcerer roll low and thus in the in-game fiction the fighter would actually be more intimidating than the high charisma sorcerer. Character stats don't tell the story. Player choices and die rolls do. In fact it's conceivable that the fighter could roll better intimidation checks than the sorcerer for the whole campaign despite the sorcerer having a higher intimidation. Who would you say was better at intimidation if this occurred?