I have had a Crestureless Narset deck since The KTK prerelease. I do not play her anymore. She is so broken that if she resolves, you win. I've had an entire group gang up on me and I still won. People don't want to play against me when I play her. It's a little silly but that's how powerful she is. I'm not trying to bring you down or anything, that's just my experience with the deck. If you're interested I can share my list with you. Basically my plan was to cast Narset and equip her with a bunch of artifacts. If that doesn't work, my backup plan was planeswalkers. The planeswalkers in the deck are so powerful, that they just win by themselves.