Here's the problem with that. Summoner was the support caster. It was also the king of Aoes. Red Mage comes in, and all that uniqueness about Summoner? Out the window. Only thing Unique about Summoner is it's low damage, Bahamut obscuring people's view, and how worthless it is overall compared to Red Mage. As it stands, Red Mage should be the lowest damage caster, with the most support. For the longest time in this game, More Utility = Less damage to balance it out. Summoner either needs much higher utility, or much higher damage. I don't care which. Black Mage and Red Mage are the only competitive Casters. There's nothing Summoner has that can rival what either of those offer.
Mudras have an 18 sec cd btw~ Ninja's Aoe is on an 18 second cooldown. Foul the big scary Aoe of Black Mage is on 30 Second Cooldown. Never mind that Fire 2 is 50 base potency stronger then Painflare, (and gets buffed by Astral Fire) Nevermind about Flare usage with their new trait. Cycling Through stuff as Summoner shouldn't be necessary. The whole point of bane is that I just spread my dots, and start the rest of my Aoe. Going through and single targeting every add, isn't aoe. It's single target dots. No different then Bard putting all of their dots and every add, except that bard can follow up on that, with quick nock, and Rain of Death.
I'll give you a better example. Look at Scholar. Scholar's Aoe is bane. They put their dots up, and Shadowflare, that's all they have. Whm has Aero 3, to dot everything, Assize, and Holy Spam. Assize is 300 potency, cooldown anywhere from 60 seconds to 48. Aero3 50 potency per add hit with 40 potency over time. Holy? 200 potency with fall off. With aero 3 one assize and one holy, a Whm did 550 potency with 40 potency every tick per add (With some falloff on holy.) Scholar would do 250 potency over 15 seconds with shadow flare, and 70 potency with Bio 2 and Miasma 2 every tick with fall off. Would take Scholar 15 seconds do what that Whm did in about 5.
This is pretty close to how A blm outperforms a summoner in aoe damage. Especially with how long it takes Summoners to use Bahamut in the first place.
Blm and Whmn outperform Smn and Scholar in Aoe. Summoner's whole gimmick since Heavensward is they had better Aoe damage.
4 Fouls every two Minutes at 650 potency with fall of damage vs 2 ahk morns every two minutes at 544 potency. Black Mages Aoe is stronger, and on half the cooldown. 2600 potency worth of Aoe with damage fall off vs 1088 damage with fall off.
Fire 2 at 250 Potency whenever they want, vs maximum 3 Painflares per minute at 200 potency.
Flare's 260 Potency with fall off that they can now use multiple times vs Shadowflare 250
Bane isn't even worth anything since the second target you dot takes 20% less damage. If you have 4 targets, you apply dots on one then bane you have two targets that take 80 potency per tick, one that takes 64 potency and the last takes 32. That's 176 potency total per tick. Painflare in the same situation is 800 potency total. (You are spreading your dots to three other targets. the only potency increase is from those three.)
Tell me one other class that has all of their Aoe's locked behind a one minute cooldown. If they were stronger, I might understand. But there are classes like Black Mage, Like Ninja, that have Aoe on command, that does more damage, with less cooldown. The only class with weaker Aoe damage to my knowledge, is Machinist. (And they never really had Aoe damage to begin with.)