The big reason why duel-wielding tanking sucks is because of "parry hasting".
The whole point of being a tank is being able to hold agro "while" maintaining very high survivability.
If your a tank and more into maximizing your dps.... then your playing the wrong class/spec.
There is a huge difference between that tank that keeps 20% threat over everybody but has a shit tone of avoidance, vs. the "lol" tank that keeps 50+% threat over everybody, yet is making the healer sweat because he/she is getting hit harder/more often then a mage that pulled agro.
Imo, everybody that rolled a DK to try tanking as a change from there "melt face dps class" do yourself, your group, and your raid a favor and look into tanking from step 1.
A good sign is if you started reading the post and have no idea what "parry hasting" is...
DW Tanking does not produce higher threat. Appropriately geared, it CAN, in some situations, produce comparable threat. At 80, Unholy, I'm pulling a consistent 1.8-2k (single target) dps while tanking. I've yet to see a dual-wielder come close to that. In beta, with full T7/25 gear, I wasn't pulling that while DW. DW'ing tank weapons does give you some stat advantages, but that is purely an itemization issue. It's a valid choice, it *can* work, but if you've been watching the PTR's you know some changes are coming down the pike that bump Unholy from the preferred tank spec and firmly put Blood in its place (and blood is abysmal with DW).
For the person who says hitting Defense cap is easy, yes, it is, but judging from your reply I'm going to assume you aren't raiding. Hitting cap is easy. Staying above it is not. I've got 5 epics that are massive threat, mitigation, and avoidance upgrades that I can't equip because they have less defense than my blues and would drop me to crittable (and that's with the defense trinkets). Epic gear, especially set gear, has less Defense on it than heroic/crafted gear. It's mind boggling, infuriating, but true. This problem isn't limited to DK's but hits them the hardest, as we have three less slots to stack defense than a warrior, 2 less than a paladin.
I'm really hoping that the BoP status of these weapons is a mistake. Then again, I was hoping the Devs were paying attention when DK tanks in the beta were telling them that we can't afford to equip our T7 because of the defense drought.
First and foremost. Can we get one thing straight. Any DK who has no idea what their talking about...please exit the forums...which is every single one of you that sad dw doesnt put out dps. I run w. a DK.dw dps who puts out over 5k easy, and i myself do over 2k as a tank.