Just went through the learning curve on this one myself.

Tips.

Most important. Stop DPS on transformations. Get Pally to spot where elemental is emerging and you'll usually pick up aggro right away. That said, be ready to use an avenger's shield, etc. to get aggro. This is a controlled fight so go slow. Once you have aggro on your pally, resume DPS.

Save trinkets, bloodlust, fire elemental, etc. until last elemental phase. This also saves you from blowing them early, wiping, and not having them for your next attempt.

Have four support toons all with strafe left/right mapped to the same key. When the mojo crap is on them just move them 5 yards.

I'm assuming your priest is holy. If so, don't be afraid to use prayer of mending, circle of healing, etc. I'd also map a /use runic healing potion macro for all four support toons in case you need it.

In summary, just take it slow on the transitions to firmly get aggro on tank and this is a pretty easy encounter.