If the goal is the shortest defeat all time, isn't the most efficient (and generally most fun) team tactic to herd? That if there's a tank, that tank (or other AT) holds aggro. The stalkers/brutes/blasters can run ahead and chew on mobs and/or bring them back. Though if more than 1 person does that, it becomes less efficient and less fun, right?
Which is why I don't understand when 2+ players run ahead and zerg around pulling the support members in multiple directions. I don't think that sort of team behaviour should be accepted as "optimal". Of course there are exceptions -- council cave maps being one that comes to mind. Personally, if I"m playing support I'll stick by the tankiest player. And if I'm playing a scrap or brute, I'll run ahead a bit and gather/kill mobs for the team. If someone else is doing that, then I'll effectively duo with them instead of running off in a third direction. It confuses me when players run ahead and they're not capable of surviving a mob; effectively forcing their pace on the entire team to keep them alive.