Devs, here's how to ACTUALLY stop speed running.

[Nadirah]

Some kind of stacking debuff on the tank or buff on monsters would solve it without necessarily nerfing threat generation (which does NOT need to be nerfed). The more enemies hitting the tank = they all get a teamwork buff and eventually we can't heal through it.

This, or this:

WoW has a few fights where mobs taken reduced damage from aoe effects. Another idea. Faction Champs, for one.