Molderahn  

Took him with my 36 ranger, camoed with a sneak backup and got right next to him and let go with Stinging Swarm, Flaming Arrow, and Ignite. Didn't notice what he was hitting me with. Let the adds go, looted, and ran like hell. Made it to CR zone with about 35%, a couple of farmers on track, but none of the elders or warriors.

i took my lvl 29 chanter had the following buffs

temp
self HP buffs
ruin

i charmed the warrior next to him and sent him on Molderahn, then rooted 1 add and mezzed the other... then mezzed the rooted add...

slowed dotted Molderahn... the warrior took him down to 45% then died .. he is rootable.. then just charm the next mob and send him in repeat as needed...

he did kill me 2 times, but it can be done..

we also had a necro inv in... cast root on a warrior and run out... all the mobs follow... while the mobs are following the necro... shammy slowed Molderahn as he came out and then he was rooted while the other mobs chased the necro, the rest of the group beat Molderahn down then we pulled the other mobs off the necro 1 at a time while he ran in a circle

Have to kill him for part of a quest. He does rampage and he casts a 450 DD nuke with root component. At least this was how he behaved when I did the quest during beta.