Sigil of Reckoning is basically a one use of Skull of the Man'ari of old, which is overall a solid effect, but the problem Standard version faces is lack of capitalizing on the powerspike it provides. Yes, Animated Broomstick exists in Standard to bolster it a tad, but has Standard heard of Soul Split?

That is why Big Demon Hunter can shine more in Wild, because it lets us double the Demons we summoned. Warden of Chains also works wonders in this deck, because she is the ideal turn 4 play to get our Health in better shape. Let's not forget slightly... more defensive tools Wild can offer to tech the deck into different pocket metas.