No, I don't think so just yet. I have played (my version of) this deck even after the nerf on Leeching Poison, and I've found a really cool dagger-like play style that just wasn't there before. My winrates with this continue to be pretty much the same, considering one of the most powerful decks against this were Shudderwock and Odd Pally. I may be at a low rank or not, but it seems like Kingsbane is still out there, although probably not for long.
My edited version doesn't have Doomerang, 1 Prep and the Sprints. Again, I may be at low rank, but Sprint seems a little slow, now that you can't attack with your weapon on the same turn.