That's why I have Displacers in my list ;)
I actually stopped an attack from RUG Delver (two Geese and two Goyf) with two Leonin and one Crusader. Goyfs were 3/4, Geese were 3/3 and I only lost one Leonin. Killed all four.
Most of the time, he stops people from attacking with anything but True-Derp (most decks are significantly lighter on threats than we are). Except that Dinosaur flavored Sneak Attack deck I saw, he had a hexproof dino and Gishath for attack triggers. I nicknamed it Jurassic Park, it looked fun.
On another note, I'm curious how a list with 2-3 Jitte, 2-3 Benalish Marshal, and 2-3 Honor of the Pure would do, sans Stoneforge.
Also, the amount of things
Zhalfirin Crusader is capable of is very interesting.
With 0 mana up - Attacks fearlessly into TNN, Strix, DRS, Mom, SFM, Pyromancer, any number of X/1 tokens, any Elf, trades with Leovold and threshed Goose, among other things.
With 2 mana up - Immune to KCommand, SoF&I triggers, PFire, kills 3/3's and survives, can also kill 3/4 Goyfs and survive.
With 4 mana up - Immune to Bolts, kills 4/5 Goyfs and survives, trades with 5/5's like Angler or Tombstalker, can also redirect relevant damage to opponent's dome, or machine-gun down opposing 1 or 2 toughness critters.
His only weakness I see is black/white removal, and very large opposing creatures (the likes of Sneak & Show, Reanimator, etc). It is worth noting his flanking only works on the attack, while activating him works at instant speed. I imagine attacking into a 4/5 Goyf with this guy, activating him twice to kill their Deathrite, and having him survive the Goyf block could become commonplace. Or... he goes unblocked more often than not and gets in for enough damage. Also worth noting that he is a Human Knight for those running Caverns, and is recruitable so likely only needs to be a one-of.