It's the tanks fault bar none, but as a BLM you have pretty much the only class that can have a "soft" opener, like the Blizz3 opener. That way the pld can get off 2 RoH combos before you start your nuke fest. Doing that in conjunction with quelling can usually keep you just under the tank for the rest of the boss battle. As long as you use quelling on cd.

As for trash pull aggro, yeah. Nothing you can really do but quelling and expect to tank the floor.