Aero + Energy Drain =/= Fester. Aero is on GCD. Fester is completely off of it. That is of very high significance in terms of DPS.

The net loss of INT alone from SMN to ACN is sufficient to dismiss this discussion. The loss of 20 INT due to the soul stone is arguably sufficient, but there's also the fact that the highest ilvl weapon you can equip on ACN is 70, versus the ilvl 90 Relic +1.

Let's say you defeated Twintania and got your hands on the Allagan Grimoire.

Garuda Egi and Ifrit Egi both have superior DPS to Emerald Carbuncle.

Enkindle and Spur have a significant impact on damage output. Blood for Blood and Internal Release, while being very potent buffs, do not make up for the difference.