Quote from benjameenbear »War of the Spark Set Review
Karn, the Great Creator – oof, this card is a beating against this deck. With the new changes to the Sideboard rules (rule #13 specifically), this card loses a lot of its attraction since it can no longer tutor for Mycosynth Lattice out of the wishboard. It’s still a decent hate-card depending on your meta, but is otherwise not quite good enough in the deck methinks. Mana Dorks are the name of the current cEDH meta-game currently, so Karn isn’t as effective as he could be.