Most people agree that the Summoner is a WoW Affliction Warlock without the Demonology art which gives the Warlock the ability to become the demon. Since WoW already showed that summoning magic can work in a MMORPG than why has Square given us a neutered WoW Warlock.
Some suggestions from WoW that'll improve upon the Summoner in Final Fantasy XIV
1. Give the Summoner an instant recast ability to absorb the Egi and become the Primal until they run out of mp.
2. Reskin the Egis so they are scaled down versions of the Primals.
3. Give the Egis a total of 8 abilities because 4 abilities is low for lvl 50 Summoner's