If we get a fourth spec, I'd be a lot more thrilled for a 2nd tank spec that is not based on the Blood Shield/Death Strike. Hell, this could even be the DW tanking spec people long for. Have it's mastery grant avoidance (on a different DR) to gain some off the "spectral blade dancer" feeling and I'd be sold. Attacks are a mix of weapon attacks and frost and unholy speciuals empowered by avoidance (like how fury is empowered by crit). And these specials grant either a short term high avoidance buff or a damage bonus. The short term cool down (blood shield, DRW) would be a ghostly minionin that haunts the enemy. AoE still has the basic diseases/pestilence/DnD that makes the signature of DKs but Blood Boil would be replaced by Haunting Shadows (shadow damage and 4s buff to damage taken) and Icy Stalagmites (frost damage and mini-root with a 4s cool down on the effect).
But since none of that is ever going to happen, that's that.