Hi! SMN main here since Heavensward.

ShB SMN was so awful to play that I raided as RDM for that expansion. I think there's a better balance to be found between the oGCD vomit of 5.0, the 2%-less-scuffed mess of 5.1, and the braindead rotation SMN currently has. I like that current SMN lets you do the "chunks" of your rotation in different orders, so you can move them around based on what movement is or isn't happening in the near future. Unfortunately, that's basically the only instance of strategic planning or forethought that SMN requires, which is one of the two core traits that defines the caster DPS role. (The other is... y'know, cast times. Which have widely been going the way of the dodo since 6.0 as well but that's a subject for a different thread.)

I like the "different batches of summons depending on which big summon just got used" idea in post 10. I get why Ifrit, Titan, and Garuda got grouped together, but that doesn't match the astral/umbral divide that's part of what defines 14's elements. You'd need to group Ifrit, Shiva, and Ramuh together with one summon and Garuda, Leviathan, and Titan together with the other to match that. And good luck getting that to make sense to someone still doing the pre-50 job quests.

Personally, I'd be in favor of nixing the Bahamut/Phoenix/Solar Bahamut divide entirely and just making them all the same button with different /egiglamour skins you unlock from doing content. Like, full clear Coils for a Phoenix skin, full clear Alexander for Alexander of course, full clear the Omega series for Omega, Eden Prime for the Eden series... what would Pandaemonium offer? Phoinix? Athena? A crowd of Ascians chanting "PAN-DAE-MO-NIUM" on cast? ...maybe Proto Carbuncle?

In a perfect world, you'd have a minor summon for most every primal and mythical creature we fight in this game and we'd pick and choose which ones to bring to a particular fight as if they were Pokemon, based on what happens in the fight and what movement is (or isn't) required during any given section. But the problem with that is that the playerbase would very quickly math out what combination of summons was the highest DPS and post it on the Balance. And like magic, using literally any other summons at all becomes grounds for getting kicked and blacklisted from PF until you use "the correct" summons.

Which is probably one of the main reasons SE hasn't bothered changing anything with SMN beyond making the class not awful to play. Now it's just boring. Which is better than awful, but not by much.