I have to agree with what teehodson mentioned in regards to going from a mastery to avoidance build.

I was in a ZA timed run with a DK and this tank had a pure avoidance build going on. He was chain pulling trash back to back to back and was barely taking any hits, and healing him was cake - in fact, he was probably one of the easiest tanks I've healed to this date. We even made it to the last boss for the timed run with plenty of time to spare.

I decided to armory him to see what he had going on (Grollix), and though he is expertise capped with a decent amount of hit, he seems to know whats going on with dk's.

I have always been hesitant to make a DK and have played a priest since the start, but seeing what this guy could do, it gave me an interest in trying one out. He stayed after the run was over and gave me alot of pointers on how to level, how to spec, etc etc - he was really cool about all my dumb noob questions and even let me real-id him if I needed any help.

I even found a site he is putting up while digging around for some dk resources showing some recent kills from the Firelands, and I can say its helped out our tanks a good bit. He recorded all of his kills from his tanking perspective and its pretty nice to see something different like that - it has definitely helped us get another kill.
http://www.youtube.com/user/Xillorg
You guys should check this guy out he is pretty beast - I've watched his bale'roc kill several times and I don't think he even got hit by decimation once - it's funny to watch a little goblin take on big bad boss like that.

Id recommend, from a healers perspective, to tell your fellow dk tank to go avoidance cause that seems to be the route a dk should go.

Just my 2 copper.

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