It'd be better to offer the option of either Bahamut or Phoenix with a shared 60s CD. Next different summon could get a perk or some buff so you alternate. To begin with, it's weird that Phoenix outdps Bahamut, Bahamut has always been more destruction and phoenix life and rebirth. It's weird they gave Phoenix to begin with. Honestly, it'd make more sense if we had got Phoenix before Bahamut.