Is this the same extort deck you have, or totally different? Lets take a look.

Lands: I'd drop 2 lands to make it 24, which is plenty in a 60 card deck. This will open up a few slots for some added control which is needed.

Creatures:

Consider:

1. High Priest of Penance
2. Vizkopa Guildmage Which plays well with your lifelink creatures from Gift of Orzhova and Tithe Drinker
3. Souls of the Faultless
4. Deathbringer Liege
5. Agent of Masks
6. Divinity of Pride

Control:If defense is your plan, then you need some removal. Bad news is that you haven't really put any into this deck. Good news is that you are playing black & white which means you can pretty much cover it all.
Creature Removal: Cheaper the better so you can extort as well.

1. Path to Exile
2. Swords to Plowshares
3. Go for the Throat
4. Unmake
5. Vindicate Awesome!
6. Oblivion Ring
7. Mortify

I have other suggestions, but lets see what you decide to do with this and we'll go from there.

Keeping the defensive approach in mind consider the following
Drop:

1. 1x Crypt Ghast
2. 1x Riot Control
3. 3x Pontiff of Blight

1. 3x Royal Assassin which plays awesome with your Blind Obedience
2. 1x Blind Obedience
3. 1x Path to Exile

Sounds good. I dropped a Vindicate for now, mostly just because they are an expensive card. Granted that doesn't really matter here on tapped out.....

Blood Baron of Vizkopa maybe to replace the Archangel of Thune . The protection from black and white makes it difficult to remove, and in a multiplayer setting, which this deck is generally played, the baron has a very good chance of being a 10/10 flyer.

I like the addition of the Wrath of God , which we talked about the other night. Honestly, to be effective with it, you'll need more than one. Ask yourself this: In a tight situation, would you rather draw Rhox Faithmender or a game changer like Wrath of God . Both are CMC 4, and in my opinion, as awesome as the Rhox is, drop it and put in more wraths.