Respect Your Elders

After the patch this achievement became a lot harder.
We had a kinda "messed up setup" for this achievement. This is how we did it, probally you can use this tactic aswell, maybe with a little tweak, or get something out of it atleast!

After many wipes as the following setup:
Healer - Druid
Tank - Paladin
DPS1/Offtank - Enhancement Shaman
DPS2 - Warlock
DPS3 - Mage (Me)

We got the main idea of it:

• 
  
• Keep Guardians FAR away from the boss
  
• 
  Boss is then not immune and can be killed quick
  
• Adds will go to the Main Tank healer, get tanked by Paladin, then killed
• 
  Adds will also get immune, but should never be, when they reach healer, if done correctly
  

We found it very very hard to do without a specified offtank class. So we tried to figure out a tactic for our group setup:

Main Tank Position
We postioned the tank and the boss here.
Nothing special, he just kept concentration up, and got threat on boss.
He was facing the boss away from the group.
This is in the "room" before you enter Elder Nadox's room, at the very end to the right, facing the stairs in front of Elder Nadox's room.

Offtank Position (or Enhancement shaman in our case):
We agreed to use our Enhancement Shaman as offtank.
He used hes healing gear, frost shocked the mobs as they came down the stairs (or just got them to himself in any way), and spam heal himself.
We postioned the offtank/Shaman here.
To the left of the stairs leading up to Elder Nadox's room.

Healer Position:
As the Shaman was doing very well on healing himself, and didn't need anymore healing than what he gave himself, we found it optimal to place the healer on top of the boss, in the paladins Concentration, because he got aggro from all the small adds (that you are allowed to kill) This made the tank get immediately aggro from the adds, and get tanked. Then Mage could AoE them down quick.
The healer could probably be positioned so he could heal both the shaman and Paladin, but we did not try this as our Shaman was fine.
The healer is positioned here. (You would know if you saw main tank position)
This is in the "room" before you enter Elder Nadox's room, at the very end to the right, facing the stairs in front of Elder Nadox's room.

DPS Positions
We had two Dpses (Mage and Warlock as stated above), we placed them on top of the healer. Warlock was just nuking boss (which he could all the time because Guardians was kept long enough away, so the Boss was NEVER immune)
Mage was killing the adds when there were 4+, or when all from the hatch had arrived. (those were tanked instantly by Paladin because healer stood in AoE.)
Position is also seen on healer/main tank map, but also here.

The Pull and Fight
So, basicly everyone except healer and tank positioned themself. Shaman stood on hes position, DPS stood on their positions. Healer stood below the stairs when tank pulled. The tank then pulled, and ran with it all the way down the stairs, then to the left (facing from top of stairs at Elder Narox), to where the DPS's stood. He got to around 50-60%, then the first guardians hatched. Shaman waited for the Guardian to go down the stairs, boss was immune untill they were tanked by the shaman.The shaman then grabbed the Gurdian (only the guardian, not the small adds those ran to main tank healer), Main tank healer got aggro from all the small adds. They were killed as soon as all were at the boss. They went to Main tank, and therefore into the Paladins concentration, and were instantly tanked.

Soon the next Guardian came. Same as before, boss was immune a few seconds, Shaman grabbed it. Adds came to Main tank healer, were tanked automaticly, then killed by the mage.

Then one more came, same as before.
I think there came 5 guardians in total.

Hope this were usefull, even if your not using this tactic, this should overall clarify the entire fight.

Soloed this with my blood DK in unholy presence. Just clear the trash all the way up to and including that ledge to the NE of Nadox. Pull Nadox with outbreak, kite him all the way to the ledge, tank him with your back against the sealed tunnel entrance, DPS him to 55%, pop army, ghoul, and dancing rune weapon and finish him off. He dies way before the guardian gets anywhere near you.

Here's the video:
http://www.youtube.com/watch?v=hEF-aPs6nZQ

As of 3.0.8, he berserks if you try to pull him to the entrance. Hit me for 87k (I was the tank)