Bungie is too busy fixing their broken,but getting better, game to come up with new mechanics. With that being said, i dont see how a triple A title cannot have different mechanics for close range bosses. Why not have a boss that shouts at you stunning you in place for a second or 2? Or casting a well at their feet that slowly steals super energy? Or a melee that does massive damage but doesnt push? How about centurion's shields disarming your equipped weapon for 5 seconds forcing you to switch weapons. How about some smaller thrall that jump on your back slowing all your movements down? They started in the right direction with the fallen glyphs that either burn you, tether you or shield allies. But they need to start adding more variety.