If I can stand on a platform and shoot a boss too stupid to shoot at me, summon defenders, teleport to get a better angle, or any other of the myriad of ways a game developer has in their toolbox to prevent some of the most obvious behaviors, then I should be able to do it. It's somewhat lazy boss design. Phogoth should not be stuck between pillars, Valus should shoot rockets into the area where people can hide and shoot him, the Archon Priest should be faster and far more aggressive with his stomps, sepiks should call fallen into the back room, the Nexus mind should levitate higher and murder anything trying to hide behind the big wall, the vex should teleport to places players are hiding. . . And on and on.