WAR has best aggro generation due to Vengeance dealing damage(which is why Sentinel is not a Role Action yet), and guaranteed Direct Crits from Inner Release and Infuriate, GNB and PLD are tied for second due to the overhealing factor from Clemency and Aurora,as well as big damage from their burst windows that generate a lot of aggro, and DRK is dead last because it lacks a lot of things to keep up with the other tanks without your co-tank using Shirk, and DRK just sucks in general so far this expansion and DRK is just going to get worse from here on out...