Hello! i am a dk tank on lordaeron in <hiraeth>. i used to MT early naxx with **** gear as deep blood until we recruited a really good prot pala that we have as MT now. Im still OT and MT sometimes though!
In early naxx we started at anub and he hit me for around 22-26k when i had 36-39k raidbuffed with flask, so yea 1 hit almost emptied my bar. Usage of runetap + and kill ghoul when i was below 25k hp was really needed so i could take one more hit before healers filled me up.
Ive used different talent builds over my time on lordaeron and ive tried frost / unholy / dual aura / and ofcourse full blood.
This is what i use today, its a dual aura build mainly focus on blood talents and highest avoidance.
http://wotlk.openwow.com/talent#j0E0...boZGgcx0MhzZMx
Ive run alot of 10mans with this and it helps with raidsetup with the melee haste and ap buff so you can skip hunter/enhance sham and when you have 1 shaman in raid he can put down spellcaster totems instead.
And this is my unholy build that i maxed avoidance for when i maintanked sartharion 3d ( let prot pala take small drakes and warrtank take whelps/elementals)
http://wotlk.openwow.com/talent#j0xZ...fgGh00bxc0t0uc
It's alot of fillers but you can argue over not having wandering plague but im just a meat tank absorbing every breath, and with glyph of boneshield.
About threat... Yes DK threat is rumoured to be crap i know and it is, especially on aoe or more then 2 targets since every ability does like 2/10 of a icy touch threat. However Frost is pretty good if you save howling for packs.
A single death and decay plus bloodboil on a pack is not much threat, a warrior can just whirlwind and he crits the mobs and they are on him.
You can whisper me here or ingame alliance dkolas if you got some more questions!
And yes ofcourse we dont have that unbalanced protpala talent AD but we have ALOT of more cooldowns to use to make it easier for the healers.