it would be cool that twins , destroyer and skeletron prime were not separate bosses and instead be some sort of "exo mech" fight where you fight it all at once that you summon with the draedon remote both in hardmode and pre exo mechs.
being clearer : remove twins and the destroyer and just put all the mechs in one fight that activates when using the draedon remote , and also removing normal calamity early hardmode progession so its possible to do the fight.