First of all credit where it's due: Props to the dev team for the job's rework, such huge changes are always going to have a strongly mixed response but I think they did right by SMN and they did a great job nailing the fantasy of playing a FF Summoner. Even if I personally find it rather boring.
The gameplay could use some work imho - it's really lacking in ways to engage with the job: decisions to make, things to keep track of or plan out, etc.
The foundation of EW SMN is incredibly solid and there are many ways it could be improved upon, here are a few ways I could see the job going. Feel free to add your own ideas.
Adding Depth
1. Rite/Catastrophe abilities replace Ruin 3 and Tridisaster with no cost (and lower dmg) instead of Gemshine and Precious Brilliance, they are basic filler spells. Damage rebalanced so Ifrit's long cast time is more worthwhile.
2. The following abilities change depending on your active summon for every summon: Gemshine, Precious Brilliance, Enkindle, and maybe Painflare. In addition to Astral Flow.
3. Remove Fester and Ruin 4, rework Painflare.
4. Reduce recast of Energy Drain and Siphon to 30s, their use resets the cd of a reworked Painflare rather than granting use of Ruin 4.
5. Gemshine and Precious Brilliance take the places of Fester and Painflare costing Aetherflow instead of attunement and have more unique effects than single target vs aoe. This could include but ofc isn't limited to: more melee stuff for Ifrit, a dot, utility, a long cast time nuke for Titan, a gap opener, an extra long range ability, etc.
6. Painflare becomes a simple damage ogcd with a short recast (12-15s), a couple charges, and it regains a charge on use of Energy Drain or Siphon. At least one use is available for each summon. It doesn't need to change for each summon but it's such a neat concept even just changing the color would be neat. This could also be designed in such a way that you want to use this under each and every summon which would affect summon timing, I'm not sure if that would be good or not.
7. Enkindle gains an extra charge, maintains its 20s recast, and you gain a charge when summoning Bahamut or Phoenix. It also gains a powerful and varied effect for every summon. Due to the recast you won't be able to use it with every summon, you'll have to choose.
8. Bahamut's filler gains a 1.5s cast time that can be buffed and made instant by one of its new Aetherflow abilities for additional weaving potential.
9. Phoenix gets some kind of combo back so it's not doing the same thing as Bahamut.
10. Astral Flow remains largely the same as a thing you want to make sure gets used with each summon.
11. And finally the least likely change to happen in this entire post: Physick finally fixed. Could have it grant a shield when Carby's out and become a big bursty heal under Phoenix.
The biggest change here is the shift in focus from blowing your attunement in each summon to lining up each summon with the Enkindle/Aetherflow effects you want. Attunement makes SMN very structured and forces you to do the same thing every time by casting a fixed number of what are essentially filler spells.
The base rotation doesn't change a whole lot though. There are many more ogcds and some decisions to make with how to spend Aetherflow as well as a couple cds to track. With more abilities changing per summon there are more options and some resources are shared between summons so you have to figure out which is best for your situation and that could also affect summon order due to the recast times of Enkindle and Energy Drain/Siphon.
With attunement gone you also no longer need to force a bunch of casts into each summon, you have more freedom to spend more or less time with each depending on how much time you have to cast, if you're able to stay in melee, if you need to move, etc. with the options that limit mobility rewarding a bit more damage.
I've seen a lot of complaints around here about Searing Light and Radiant Aegis. I think they're fine as is, the longest period of time you go unable to use Aegis is much shorter than its duration, just plan ahead a few seconds. And the buff you want to use before Bahamut/Phoenix anyway. But if a change were made I think it should be to either give Carby more stuff to do or remove it entirely. Neither seems necessary imo, I rather like the little fellow but I wouldn't complain about it gaining another ability or two.
Building Up to Summons
FF summons have always been big and flashy to the extreme and while Endwalker captured a lot of that visually it isn't really felt in the gameplay, especially with Bahamut. These ideas focus on building up to the big summon attacks with trance for every summon.
1. Aetherflow and Arcanum become one and the same, granted by Energy Drain and Siphon. From here on out I'll refer to the resource as Arcanum.
2. Arcanum is used to summon Ifrit, Titan, and Garuda as it is in Endwalker, however on use each Arcanum transforms into another resource which is used to summon Bahamut and Phoenix - you'll need 3 of this transformed resource to summon them (similar to Stormblood SMN). An extra cd can be added to speed up this process every couple minutes for the opener and recovery (see 3f).
3. Ifrit, Titan, and Garuda all function differently:
3a. You begin with an instant cast which grants a trance bar and changes your abilities but there's no big primal attack (yet).
3b. You cast your transformed abilities to fill up the trance bar.
3c. Using transformed abilities causes a ghost of the primal to appear before you for a brief moment attacking with you.
3d. Each summon grants you a more robust rotation with its own identity. Ifrit is primarily melee (with a weaker ranged option). Titan is slow and short ranged with more cast times and a focus on aoes like lines, cones, and point blank circles. Garuda is fast and long ranged with more mobility including a dash.
3e. Once the trance bar reaches 50% you can execute the big primal attack with a 3s cast. This attack gets bigger the more trance you have, both in numbers and visually. This attack is required to convert the Arcanum for Bahamut and Phoenix.
3f. The aforementioned cd to speed up the path to Bahamut could have your next few summons start at 50% trance so you can cycle through them quickly.
4. Bahamut and Phoenix would work similarly to Ifrit Titan and Garuda but they would always be out as they are now and their trance bars would fill up much faster allowing you to spend it on multiple abilities before ending with an ultimate attack.
More Summons
If there's one thing nearly all SMN players can agree on it's that we want more summons, even if they're just glamours.
Implementing more summons can be a little tricky because each additional one is another button on your bars (unless SMNs get some sort of cheeky Mudra summoning system). On top of that if there are a handful of different abilities that change for every summon, adding more summons forces the player to remember that much more so summons would have to have less cool stuff so as to not overly tax players.
One way around this would be a loadout system where you pick a few summons out of combat but I don't see SE doing that ever for non-limited jobs. Or glamours which wouldn't change gameplay at all.
I'm going to look at the simpler summon route building off Endwalker SMN, though most any of the ideas listed above could be added here as well.
1. Add 2 normal summons to go with Ifrit Titan and Garuda, and 1 big summon to go with Bahamut and Phoenix for a total of 8 summons - the 3 big summons each have their own ability so you can freely choose which you use (8 seems like a good number for controller players).
2. EW SMN goes through summons pretty fast already so the rotation of 3 normal summons for every big summon will stay the same.
3. There's only one kind of Arcanum and it can be used for any normal summon. The big summons are still free.
4. Normal summons gain a 45s recast time, big summons gain a 1.5m recast time. This simply prevents you from spamming the same summons.
5. Each summon has a purpose. One could have a maintenance effect like a buff or dot so you only bring it out to refresh that, one could have exceptional mobility or the ability to attack two targets at once no matter how spread. I'd avoid making any summon too niche however lest they get ignored. Each should be similar in terms of dps with the potential for an edge in certain situations, like cast times vs instants or melee vs ranged.
6. One more ability like Astral Flow would be nice, could even be solely for utility.
I'm not a big fan of the "Bahamut > summons 123 > Phoenix > summons 456" idea, I'd rather break up that structure and have more freedom of choice. I've always seen the FF Summoner as a toolbox job with a summon for every occasion, there just aren't a whole lot of occasions in an mmo. Perhaps such occasions could be forced onto the job artificially through a gauge of some sort... but that feels constraining in a different way. A very rudimentary example would be getting buffs to certain types of damage or reduced cast times. Thoughts, anyone?