Dragonshift will just win you games immediately when cast.
So you would move into UWR solely because of Dragonshift? I haven't been valuing it that highly (as in, as a card that would push me into a particular set of colors), but I'll be on the lookout for it in the future.
This is what I ended up submitting:
The plan was to clog the ground and fight in the skies, using random Extort triggers to get some extra reach. I ended up going 2-2 in the tournament, and to be honest, it looked like a 2-2 pool when I opened it. I don't know how much of the result was me living out a self-fulfilling prophecy, but that's what happened. The mana was fantastic the entire time; I never felt like my deck was screwing me out of victory.
Match 1 was interesting. Game one was a grindy affair against a mediocre 4-color monstrosity. He had nothing notable other than Skylasher, which he did manage to "get" me with in game one, but was easily played around from there. The only damage I did to him was through extort triggers and the Hired Torturer. Game two was a flat-out race that I easy won.
Match 2 my opponent is on Jund. He attacks into my Skymark Roc with his Daggerdrome Imp; it seems obviously correct to not block, at which point he slams a Swamp followed by a Rakdos, Lord of Riots. Fantastic. By the time I draw the Detention Sphere, it's too late. Game 2 he drops a Gruul War Chant and I simply can't block or race profitably anymore. He ends up being the winner of the pod.
Match 3 I faced the Auras guy, with multiple Unflinching Courage and Madcap Skills, plus the oh-so-clever Treasury Thrull to get them back. Fortunately, I had enough removal to make him regret going so all-in. Game 2 was particularly memorable, with me winning even after he gained 20+ life over the course of the game (mostly through temporary pump effects on Daggerdrome Imp).
Match 4 was miserable. My opponent was on Grixis, with hardly any creatures. Game one he just sat back and rode a Stab Wound to victory; I couldn't stop it or race it. Game two saw him do literally nothing but rip burn spell after burn spell. His deck had so many burn spells that the Izzet maze runner actually did serious work for him.
Final result: 2-2.
Looking back, it's entirely possible that Dragonshift could have turned the tide in games that were otherwise unwinnable with my deck, just from the surprise factor alone. I just felt that black was deeper, with more evasive threats and better removal. The Cancel came in for the Leyline Phantom in almost every game, so they probably should have been switched.