By now, everyone is in on the joke that is the theme of Death Knight tier sets: skulls, and blades, and skulls, and bones, and skulls. SoO actually had a refreshing departure from this theme (who knows what it was though) and there was also the Magma Burger King tier.
I'm jealous of the crazy variety other classes get sometimes. My Shaman gets some pretty diverse options, for example, from primal sets to elemental sets to wolf sets. But since the theme of the DK tier sets always seems to be deeeeeeeeaaaaath, what other themes can you imagine that would stay true to the class but not be the same skulls++ again?
For example, I would like it if they acknowledged our spec lines in a tier here or there. A Blood themed tier would be pretty neat, maybe something similar to:
...but just slightly less spell-caster looking. Something vampire or bat related. Or a Frosty set like my Shaman's T11. Or even some sort of Runic set to pay homage to our unique resource system. Just something to acknowledge there is more to the class theme than "emo warrior".
What ideas would you like to see in an upcoming tier?