While I am totally against gear swaps in combat we kind of already have them. Most EG BRD's I know have a macro to disengage, equip their AF, cast a song, reequip their 2x/3x melded gear, then reengage, takes 8~10 seconds. Only person that can't really gear swap is the tank and your tank should have their gear set before engaging anyway. Just no crap like XI, I needed 8 staffs and extra gear just to cast certain spells, that was a joke.