Managed to kill Wyrmy just fine a few times this weekend.

Used the following strat:

Parked group close to edge of his platform. Tanked him up top till I spotted the adds. Focused the ogre for sheep. Soon as the adds were in range the mage sheeps the ogre and the hunter puts down a freeze trap. Tank jumps down with the group on follow. The orc would be trapped.

At the bottom I heal up whoever needs to be healed and wait for Wyrmy. Managed to finish Wyrmy off before the CC on the adds broke and then it was easy dealing with the adds.