As people have pointed out, if its not something that noticeable or a game changer in combat, why take the time to make it; would seem like a waste. Now, more aesthetic differences or things not pertaining to combat sounds like a good thing. Things like the Ninja having a unique jump animation, and come 4.15 we'll see if the musical feature requires you to play a BRD or have BRD leveled. Such little things like that would be cool. I wouldn't be adverse to certain jobs getting this or that, WHM got a mount way back when for a side quest, maybe DRGs could have a side quest unlocked to only them where maybe they do get a Wyvern they can summon as a pet with actions, just no actual combat function.