At first glance, Feign Death seems totally bonkers. I mean, your usual Hunter runs: Webspinner, Leper Gnome, Mad Scientist, Haunted Creeper, Sludge Belcher, Savannah Highmane. Hitting a single Highmane gives you two 2/2s, hitting Scientist is a bit like having had a trap in hand instead, and any two of the others is mostly good value for a 2 mana card.
On the other hand, one of the strengths of low-curve decks like typical Hunters is to reliably play on curve. This card doesn't help you do that. It's also a bit win-more in that it does best in situations where you're already ahead. I could imagine it edging out Houndmaster for inclusion, since Feign Death can find a target more often.
Seems really weird to add a card that's a direct buff to the strongest deck in that game, in any case.