Second boss
Have one dps stand on top of the ledge where you killed the NPC with the cannon before the boss fight. He is the one keeping the aggro the entire fight. Once boss aggroes to him, he'll run to the door and keep running stuck (for quite a while), this is when the rest of the group dps-es until aggro switches to the one who does the most damage. When that happens, just run back to below to where the guy on the ledge is standing so he gets the aggro again, and then repeat.
Third boss
A bit more complicated.
Everyone but one guy with stealth stays outside the room, where the door closes when the boss fight starts. Before the guy with stealth runs to boss, healer spams a ton of HoTs on him. The guy then runs to the boss, gets hit, door closes, gets healed with the HoTs healer put on him beforehand and in a sec or two the aggro should switch to the healer that's standing behind the closed door, outside of boss room. When the aggro switches, the guy inside pops stealth and goes sit in a corner. The boss then runs to the door trying to attack the healer, healer stands a bit back away from the door and the 3 other damage dealers outside the room use normal melee attacks to DPS the boss down (can't use skills). The boss is stuck in the door the entire time, so you can just go afk for like 3 minutes while auto dpsing him. Mind you, you won't actually see the boss from outside the room when he's stuck in the door, but you can target and hit him.
Fourth Boss
The fourth boss stands before some doors. Just run around the boss to doors, open them using the two lion heads, then go to the next room, clear the NPCs, fill it with water, then go pull the boss while you remain in water. The boss will run to the edge of water and get stuck there, and you can just dps him down without any tanking. Don't go into melee range here!
Fifth Boss
Also slightly more complicated. Everyone stays outside the boss room. The healer grabs the big crossbow from the boss room, stands right outside where the doors close when boss fight starts. He shoots the boss with the crossbow (has big range), drops the crossbow. Now when the boss does his channeling spell on the healer, healer starts running back to the room with water, while healing/HoTing himself. He needs to reach the water before the channeling spell is over, and he needs to stay in the water the entire duration of the fight. The boss will get stuck in the door again, but this time you'll see his head pop out of it and you can use all your skills on him to damage him down. So the rest of the group goes to the edge of the room before the boss room, waits for the boss to get stuck in the door and immediately starts dpsing him down. Remember, healer/the one who pulled needs to stay in water. Enjoy the boring fight once again
nice game eh?
