I've been doing pretty well with this deck in masters, if you're questioning the scuffed powerbase its because I don't own any crest of cunnings but I haven't been power/influence screwed at all yet. Please let me know what you think and add some suggestions!
I think one of the strongest points of this deck is being able to draw answers from the market many, many times. Just having one merchant grab mirror image generates an insane amount of value, and it enables you to take control of the game very quickly. The only market card I am not sure about is maul, I have not used it in any of my games, however it is a good finisher. If you want to replace a card in the market, I would recommend Maul as it is an ambiguous slot.
Edit: I know Vara is sort of anti-synergy in this deck but I haven't taken the time to find a replacement yet, also removed initiate of the sands because it didn't seem to be doing much to ramp towards Caiphus, I replaced it with permas instead.