I was putting this together right as Khans came out.  Mantis Rider is insane and for a while other people realized it and it had a price jump from $2 to $7.  I didn't pick them up, and now they are back down to $2, so I'm trying to pick them up on the cheap again. 

Loxodon Smiter is a fine vanilla beater.  The can't be countered, and built in resistance to 8 rack is huge. Savage Knuckleblade looks like good value also, but I'm not convinced.

Bant Charm is also a thing which might be better than putrefy, but it's harder to cast.  Instant speed removal is important in a match up vs something like twin.

More info about the deck:
http://www.mtgsalvation.com/forums/the-game/casual-related-formats/573583-nayan-crusaders

edit: Feb 25th, 2015 starting to think about putting this together again, sadly Wilt-Leaf Liege has caught on in somewhere or something because they are suddenly $30 each.  This makes me sad, but subbing in Boartusk Liege actually pumps most of the guys I wanted to pump anyway, it just doesn't have the resilience vs discard.  I think it's synergy with BTE might make up for that though.  Mantis rider is also down at the moment and I'm trying to get those while they are down.

Another angle of play might be to add in multi colored counterspells and play it as a midrange build.  I could see Mystic Snake, coiling oracle and cards like Counterflux being playable.