My guild did this part 3 times the other day. The Corruptor is cake. 51 ranger and monk, and a 52 druid. We only needed 2 heals from the druid each time. Keep him rooted. Monk hits fast so he didn't get much time to get spells off. The important part is: once you do the turn in to teola you do not have to follow her to the gathering. Druids can gate. We rangers have to hike it back up the hill. Know the loc or track a party member back after you turn in to teola and you can be sitting there waiting for the spawn.
The reavers are a bit tougher. We had a full group on the reavers and most of them were mid to high 40's. Bring a bard and have the bard mez and charm one of the reavers. If you time it right then they won't have time to summon their pets and buff themselves. Out of 3 tries only one pally died. She took the HT (yes it is 551 per) and couldn't drop aggro. With a little planning this part of the quest isn't a big deal.
Aubric Mistkeeper
Pathfinder of the 51st season
member of the Raincallers
Povar server