SE, don't overthink Summoner 7.0. Just give people what they want. Just do it.
Leviathan.
Ramuh.
Shiva.
That's. It.
Please. Don't overthink this. Don't do something weird and pointless.
We don't need "Ruin 5".
We don't need "Summon Bahamut II".
We don't need "Energy Vacuum".
We don't need some weird fourth gauge that we consume to ride Susanoo around like a mount for 15 seconds and force enemies to engage in Active Time Events.
Please. Don't try to "subvert expectations". Don't.
Just do the thing.
Just give us the rest of the Classic Final Fantasy Summons™.
Just do it.
"But the Lore says that they need to come from a weird mutated Carbuncle gem, or something!"Okay sure, here:- Aquamarine Leviathan
- Amethyst Ramuh
- Sapphire Shiva
There, done. Let's move along.
"B-But you can't summon Shiva! That's blasphemy!"Sir and/or madame. We've been carting around Louisoix's desecrated memory like a designer handbag, in direct disrespect of his final wishes, for 4 years now. The ship of sanctity sailed back in Shadowbringers.
What matters now is, "Will this increase pre-order purchases if it appears during a Live Letter?" And the answer — which SE's board of directors will be happy to hear — is a resounding, YES!
So not only will this make Summoner players happy, but it will also increase SE's revenue, which can then be reinvested back into Forspoken 2. Win/win! (?)
And anyway, you can think of it as honoring someone's memory, rather than an enslavement — since we are, after all, just play-doh'ing Carbuncles into effigies of Primals... not actually performing a true summoning.