Why the Arid Mesa and Scalding Tarn? You don't have anything with Landfall, which is the only reason I can think of running those instead of more Mountains.
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Looks solid. Only thing I'd recommend is maybe fitting in True Conviction or Accorder Paladin. Also, if you have two Knight Exemplars out, you can wipe the board with a Day of Judgment or Wrath of God, but all your creatures would be indestructible and unaffected.
Why not round it off to an even 60 cards? Elven Archdruid and Ezuri, Renegade Leader would be pretty nasty with this.