Totally true. But for many people, comparative advantage or comparative equity isn't the problem. The problem is more likely that the entire grand scale of the job can be had in approximately two hours with enough anima and a good party. Or, regardless of the time, the fact that the player never once made a unique decision in keeping with a "dragoon" or pursuing that role. You merely took a little extra time while leveling a strand that levels almost identically to every other strand.
It leaves a raid team basically estimated by how many good knives they can bring to a gun fight. They all cap out at about the same places, which should be fine in the name of balance, but to many none of those caps feel satisfyingly deep.
I don't think it's unreasonable to feel like jobs should be more than just a collection of tools. I'd personally rather have the collection of tools be turned into a more unique job or few jobs that both better define the player, and the player more choice-fully defines for himself.
And again, if changes were to be made to aid this, it probably wouldn't come from any 'adjustments' to the armory or job systems. It'd have to start further back.