A little history of farming for the newbies:

Swamps:Bayou Boss Brawl
The bosses were in the corners, with an open space in the middle. This led to the Pull, whereby one player 'leashes' a boss, brings it to the open space and the other players kill it. Then they remake without killing most mobs.

AO1: (Last board)
There were two bosses very close to the beginning, so players would kill those two, and remake without killing most mobs.

AO2: 4+5
The Dev's decide to counter this by putting the bosses at the end of corridors of mobs so the players would have to kill them to get to the bosses. The players counter this with rushing techniques where they use stuns and ice skills to run to the bosses and kill them, and then remake without killing most mobs.

AO3+ : Doors? Could there be doors that can only open after killing the mobs in the room? Would this prevent players from remaking without killing most mobs? If so, will it be countered?