There is no Final Fantasy that lest Summoners summon the boss Primals usually it is a weaker version of the actual Primal or summon. There is nothing wrong with Summoners summoning the primals. The Egi's and Pet system does need to be redesigned to make them more balanced like Ifrit they need to get rid of radiant shield and give him Radiant Plume and Eruption. They also should make the Pets more detailed and look like the primal.