Non lineal dungeons. ARR dungeons were kinda like this, where they were more like an instanced zone where you have a path but still relatively free to go where you want, whereas newer dungeons are literally hallways. They're designed to be zerged because the devs know people just rush and pull everything on sight anyways. God forbid they add something like a jumping puzzle, or step on the right tiles, ride this NPC, or any other unorthodox mechanic