Plothozz is easy for a group of mages. I was in one last night and we were spamming heal and sharing aggro. I also finally was in a party where a bear could tank and hold aggro. My advice is to not attempt him until the party is close to level 45. When I see a bunch of people in the 30s I just leave because I know we won't beat him. They're too low to do any damage assuming they can hit him in the first place.