I don't know your build but maybe you could to well with Obsidian Shield. It's an AoE dmg shield which is twice as strong for the DK and you gain stamina when using it on other players.
Ye, that sounds sweet. It doesn't go towards solving the lack of AoE, though. So perhaps I'll have to swap it out when fighting trash.
Based on my experience in other mmos AoE tanking requires a great deal of AoE damage. In for instance WoW, Warrior-tanking without thunderclap would be a pain.
I understand that threat will work differently from any other games I've played, so perhaps its not as big of an issue as I think?
I hope someone will make an add-on which would allow you to save and change skill set-ups by pushing a button. That would allow for some fun strategic gameplay.