I can glimpse their plan.

Add Ramuh, Leviathan, Shiva then make the rotation like this: Bahamut (opener) > Ifrit, Titan, Garuda > Phoenix > Ramuh, Shiva, Leviathan > Bahamut > repeat.

No more buttons, just different colors of the same thing. Literally, a 'summon machinegun'... something SMN never was in any FF that I can think of.