As for Tanzlee's comment about Durumu being the easiest ToT LFR boss I politely disagree; that title goes to LFR/Normal Primordius as you can literally stand in one spot the entire fight and spam your rotation until boss dies. Killing oozes is optional and until Blizzard actually fixed Primordius' damage reduction against non-mutated players that's how early Heroic Primordius kills were done provided their healers could handle the extra damage intake.
However I will say that Durumu is one of the easier bosses in ToT LFR. In ascending order of difficultly (e.g. individual player responsibility on a raid-wide level) I would rate LFR ToT bosses in the following order:
Primordius -> Tortos -> Jinrohk -> Durumu -> Twin Consorts -> Megaera -> Council -> Iron Qon -> Ji-kun -> Horridon -> Dark Animus -> Lei Shen
Edit: Here's a kill video showing how "hard" Heroic Primordius was before the nerf.