I think at best the flavor text that says that Clan X excels at Class Y will make those places where NPCs tend to have those jobs, and maybe there will be class-related quests in those areas. e.g., going to the dark Elezen's town to learn new Pugilist abilities.
Ok, now we're going to get slash fiction of Wint x Kachi somehere... rule 34 and all...
Never confuse your inference as the listener for an implication of the speaker.
Good games are subjective like good food is subjective. You're not going to seriously tell me that there's not a psychological basis for why pizza is great and lutefisk is revolting. The thing about subjectivity is that, as subjects go, humans actually have a great deal in common.