it's more than enough to slow down aggro, which a lot of people are gonna run. if the maggot DOES die, they take 3 as opposed to you taking 2. with all the extort on the field and the priest of penance, it's gonna force a simple aggro deck to think, instead of just swinging balls out. it can't be doom-bladed. if it gets returned to a hand, it doesn't "die", so the card remains exiled (judge ruling?) once athreos is a creature, block w that or the priest to blow up their shit.
Permalink
thought seize is good, but pricey. run the new creature "Brain Maggot". does the same, but for 1 mana more you have a blocker. With Athreos down, you can either do it again OR they take 3 life.
+1 for Prophet of Kruphix/ Hypersonic Dragon. It's a long set up, but devastating.
+1 for Priest of Penance in lieu of Basilica Guards.
as for more control... the new card "oppressive rays" (1 drop W).. and banishing light (2W). cheap and effective. with blind obidience on the field, you'll still be able to extort without tapping out.