I just wanted to cheerfully proclaim that I have come up with a powerful new deck (which uses NO new cards from March of the Damned, I might add) that has beaten both Orc/Skaven and BT decks, with surprising consistency. I'm getting ready to test it against Dwarves but I suspect it'll have the same success.
That is all. Had to celebrate but not presently willing to share the build just yet. Sorry for the tease. I'm rather shocked that it hasn't been created already but at least on these (and a few other) forums, I've not seen it. Totally cool. Man I love this game.
Good guesses, though incorrect (both of them).