We’re starting to think that the ship has just sailed on Pestilence. As I said, our original intent was that Blood Boil be the main AE attack, but now we’re considering making Blood Boil more for tanking, letting Frost use Howling Blast and letting Unholy use Pestilence, because, you know, diseases.

That is a really great idea. Have you given any thought as to how you would implement it? Like would Unholy be the only spec that could spread full strenght diseases?
Something like that. Full strength might be too powerful, but we’ll see. Unholy still has a few too many talents like Improved Icy Touch and Corrupting Strikes, so this might be a good replacement (though likely deeper than those two examples). (Source)