As the title indicates the tank dk in our raidteam has some problems with threat. For example this night on Iron Qon 10man after a tank swap our warriortank can barely touch the boss or he'll overaggro from our DK. He has to consistently disable autoattack and shadowmeld to make sure he's not overaggroing after a tankswap.
I'm not yet able to post links according to mmo, if you can take the time to go to them manually it would be very appreciated, our guild is called Symbiotic on EU-Stormrage.
Any thoughts on what he should do to improve his threat?