What we have here is a brand new better cheaper Warlock deck - a Cubelock with some big deathrattles and Soulwardens. The way I see it, if you're already running Expired Merchants, Soulwarden becomes a 6/6 with battlecry: add two Bloodreaver Gul'dans to your hand.

Yeah that's as far as the good changes go. Sylvanas Windrunner and Sneed's Old Shredder are there only to run up the deck's dust cost gain an edge in control matchups ok I know this looks bad but there's a reason to run them trust me.

You don't need Mistress of Mixtures or Zilliax or Defile, the deck is too optimized to run anything that doesn't directly synergize with it. Staying alive against aggro isn't integral to your game plan of playing 7 Bloodreavers just because.