I have recently taken this deck to champion. New enchantments allow rainbow OP to have considerable value in the late game, between whitemoon arena, guardian plateau and moon in the water. You can add in sword saints if you feel you come across a lot of aggro, but I generally dislike playing sword saints in my decks.
We usually want to have a desert down early so we can play Mardykhor on curve, and later replace the deserts with other enchants to get back mana. Rainbow path really opens up a lot of plays by replacing our expensive enchantments with cheap ones and ramping our mana. A lot of synergies in the deck exist to make use of this excess mana. Ifreet/barkeep into whitemoon arena is one of the strongest things this deck can do, as very little stuff can kill ifreet/barkeep on curve, which allows Whitemoon Arena to snowball.