Tanks using their enmity combo while being OT

[Fyce]

That really applies to War/pally combo though. Not home so can't look up drk at the moment. It also assumes that the MT is being optimal. But really they should have a decent hat lead.with their opener.

DRK is worse. You lose 130 potency if you do a Power Slash instead of a DA'ed Soul Eater.
PLD "only" lose 80 if they do a RoH instead of a RA.

In comparison, a WAR going SE > SP instead of SE > BB will only lose 40. (SE > SE only lose 20.)

The difference is so huge that I'm not sure buffs and tank stances would even change that.

So, in short terms, the goal is to allow the MT (DRK or PLD) to do as much DPS rotations as possible during the entire fight. If the WAR OT reduce that number of DPS rotations from the MT because of its BB combo, then the overall raid DPS will be lower.
Same goes for forcing the MT to stay in Tank stance longer to compensate the high enmity of BB.