on the navigation screen, the Y button normally is for switching loadouts. however, while a mission vote is active, it can't be used for that and there's no other way to quickly switch loadouts. going back to the arsenal segment takes too long because, by the time i've finished loading after a sorties mission, the vote has usually been waiting for me already and a lot of the time someone has already pressed the button to start the countdown
in short: because it's often necessary to swap loadouts as quickly as possible between sorties missions, there should be a very quick way to do so even while a mission vote is active