another one of these?

my take on the lore and how the job was implemented in this iteration is that instead of summoning carbuncle, you instead are able to conjure a fraction of the primal's real power; hence it doing more damage than your carbies. as summoning the primal itself takes a lot of summoners to begin with, it is only wise that such degree is only possible. mind you that it can change in the future where you get to actually form a bond with the primals and let you, being the warrior of light, call upon them and grant you a more potent versions of your egis. the lore is very much open. it's just how to implement them is the challenge.

on a game standpoint, don't forget that this is a mmo. implementing the old style summoning magic isn't possible. the nature of a pet class is and will always be supportive. it so happened that this game made it a dps class and reiterating what i mentioned above, future expansions will address it. how soon it is, no one can tell.