I'm finding that depending on the group, a two tank method may be better for the post-Heavensfall phases. My group (wanting to get a clear for someone to be in our raid) kept pushing the phases badly at that part.

We kept wiping again and again because a heavenfalls would come just as Bahamut's Claw occurred and our tank would get smeared into the ground. Phases are weirder now because of the ilevel increase AND the echo buff. :/

If DPS push it too much later on, switch it and have another tank come in just to hold back the fight a little.

However, in your case, seems like your dps are just running around like chickens. Lol