I think you're going to have to expand on this, because it sounds like you're saying that because there are some new sets with taunt auras, it means the whole AT's intended team function should shift. That's like saying that since some newer Stalker melee sets have more AoE attacks than earlier ones, Stalkers should be an AoE damage AT now. And because you can build for better defenses with IOs, Scrappers should be encouraged to take the aggro of bigger and bigger spawns, simply because they can survive it now where they couldn't before. But that's true of every AT, and by that logic you could claim that Defenders or Blasters should be able to manage aggro, too.