I've featured some W/X midrange decks in this column, but nothing like this before. Instead of killing with Brimaz, King of Oreskos (and potentially Wingmate Roc), all we have here is a pile of planeswalkers backed up by the best Mythic in M15.
Clearly I'm talking about The Chain Veil.
Alongside Liliana, Sorin, Ajani, and Elspeth, The Chain Veil might actually do a ton of work. You only need one copy because Liliana Vess can tutor for it in a pinch. The other big shocker is another M15 sleeper: Scuttling Doom Engine. Even if they have a fistful of removal, a couple Doom Engines should be enough to finish them off, and it doesn't matter whether they live or die. They're also quite good in planeswalker mirrors.
It's worth noting the Phyrexian Revokers, Stain the Minds, and Decide in the sideboard, clearly meant as hate for the Jeskai Ascendancy combo deck. Clearly those cards have other uses, but between them, Thoughtseize, Utter End, and End Hostilities, I wouldn't be surprised if this deck had a very good matchup against Ascendancy decks, whether they be heroic or straight combo.