I think there should be key binds for when the Ghost is pulled out. D-Pad could then function for the ammo synth. If it were a PS4 only game, they could add swipe functions. As for the change of weapons on the fly I've been reading, it's not necessary. If you don't know a good loadout for the current mission you are playing, then you haven't played it enough. Or you don't use checkpoints to your advantage. For instance, I know that the Suros is my go to for the first half of the raid. This is so I can get those nice stumbles on the ads. Before stepping into the throne room, I'll switch to my Vex so I can get 1100 crits on Atheon.