1. If you have good chanters, you can charm the Rak (among the adds) and use him for dps on VL or the projection.
2. When your raid has (a) a lot of healers or (b) hi dps, you can stop killing the Protectors entirely and just heal thru the dots. As others have said, DON'T cure them, just heal thru.
3. Otherwise, we put a bunch of casters and a knight permanently upstairs, and melee downstairs. Upstairs, they just bomb the VL or projection, when they can and kill the 3 protectors when they spawn. Melee can go to the 2 downstairs as needed.
4. Always debuff the VL when he spawns and VL & Projection at 50%.
5. Time it (pull off dps if you must) so you don't have protectors and adds at the same time. 70%, 40%, 10%. Kill the protectors, then back to dps on Bosses till adds come, kill adds, etc.