Originally Posted by
Havenae
This isn't a valid reason to not have a gunblade job. Pretty much EVERY job in the game it is insinuated that you are the sole custodian of that soul crystal that allows you to take up the job. Meaning you're pretty much the only one other than the rival you may or may not have in your job quests. This is why the majority of NPCs in the game don't have jobs, they have classes, even the scions.
Other players? As far as the story is concerned, they dont exist. you're the solitary warrior of light. The people you group with for dungeons and trials are just your comrades that you call upon for assistance. You're the hero, not them.
So rarity really isnt a factor.