Okay, so I spent at least 5-6 separate attempts with different groups trying to beat Titan HM. I was the weakest link - I would get booted off the side and leave my fellow healer struggling alone to keep up, which doesn't work.
I could zip and dodge everything but the bomb phase. I struggled to see the dumb rock pattern and to see which "line" dropped. I'd inevitably run the wrong way and get land slided or blown up or both.
My epiphany came with this: If I could at least avoid the landslide, I could survive a direct bomb hit from full HP.
Instead of worrying about the bomb pattern, I just said screw it and worried about dodging landslide. As soon as I got smacked by a bomb, a fat cure on myself solved the problem and then I could worry about curing everyone else afterward.
Curing priority needed to be ME first throughout the fight. Not the tank - that was number two. Third in line is the other healer. Only then should you worry about the DPS. Once you're past the heart phase, it's just a matter of slowly wearing him down while dodging all his crap, and losing a DPS or two won't make or break the battle (we were down two DPS by the time we won.)