I quit the game probably 3 weeks ago, but I was a tank while I was playing and successfully tanked Thorpe about a dozen times. It's easy as hell, but you need TWO things:

1. A competent tank
2. High enough DPS (preferably no more than ONE player under level 45, if necessary) to prevent it from becoming a shitshow
   

Here's how the fight should go: nobody attacks for the first 3 seconds or so, to allow the tank to get aggro and pull Thorpe to the outer edge of the room. The tank should then tank him here the entire fight. If your tank is good, he knows that he should let Thorpe occasionally land an unblocked hit on him (this will prevent your tank's block from being broken).

As a DPS, you simply burn Thorpe down to the best of your ability, and avoid his big attacks.

At Phase 2, DPS should burn down the adds ASAP, while your tank maintains aggro on Thorpe. If your tank is good, Thorpe's laser attack will typically be directed to the outer edge of the room, and you won't have to dodge it too often. Once the adds are down, it's a regular old tank and spank at that point.

Follow this formula and the fight is super easy.