You deck seems like it needs a lot of mana and you will be casting at most one spell per turn IMO as long as Crypt Ghast is not in play, I think you should remove the 1 Treasury Thrull you have there and add 1 more Crypt Ghast

Also if you plan on gaining life you should definitely add Vampire Nighthawk I think, not sure, it seems not that consistent when I play test it, this are my suggestions, let me know how it does

Also check my attempt to Orzhov, is a complete different idea, but let me know what you think deck:you-better-pray

i hear what you mean about the mana, but my defense is that Treasury Thrull brings back Cathedral Sanctifier which is basically used as fodder once its ETB effect is through. So this way, i get to abuse that lifegain with combos. Vampire Nighthawk is obvious, but i'd like to keep it out just to try and function without it. so far every creature has a real Orzhovian flavor to it and i just don't think vampire shamans fit in that motif. i can probably take something out for another Crypt Ghast for that help in the black mana department, for sure.

I would check out some kill spells, at least for side-board. Ultimate Price and Tragic Slip can help get rid of some major threats you might see. Other than that it looks pretty solid! I'll do a bit of playtesting when I get a chance later! +1

ah yea i had Ultimate Price involved instead of Chalice of Life  ^Flip originally but i was afraid that the mono-colored restriction was too narrow... i could always reserve Oblivion Ring for gold threats, but i'll definitely keep playtesting and see if i can fit some kill spells in somewhere. Killing Wave is the only one i have at the moment and its only for situations where i actually benefit, like preparing for Immortal Servitude or something... i do have one Merciless Eviction i can take Treasury Thrull out for if its not consistent enough.

I really like the way this deck play tests...I'm having a little trouble with my deck all your life are belonging to us (help!) so I might modify it to play a bit more like this.. My problem is with the love I have for some of my cards lol. Any advice you would like to give please do....

Vampire Nighthawk with Ethereal Armor . Awesome defence (first strike + deathtouch); Awesome offense, especially since you got quite some enchantments; and last but not least, awesome and quite assured lifegain.

Imo, it's worth consindering 4 of both as both will fit nice without each other as well. You could remove the Basilica Screecher , Divine Deflection and Murder to fit for Nighthawks and another Blind Obedience . Not all too sure what to remove for Ethereal Armor s, but if you add them you should probably go for more Blind Obedience and Oblivion Ring s/Stab Wound as well

Blood Baron of Vizkopa and Chalice of Life  ^Flip look like a natural fit. Baron is a terror if the prot black/white is relevant. I've got two Orzhov decks along the drain life theme - not much extort in them, though.

I've thought about Crypt Ghast to fuel Debt to the Deathless , but am currently of the mind that it's too slow in my decks. I was hoping to activate Vizkopa Guildmage then getting 3x damage to the opponent, but it was 7 mana just to pay the initial costs, so X wasn't getting very big.

In case you are interested:

My Gain is Your Loss

Sustain the Gain

Agog, thanks for the references! just yesterday i pulled off the Crypt Ghast /Debt to the Deathless combo, and yea it was late game but it was a great finisher! and i used to have Chalice of Life  ^Flip in the deck but opted to remove them for kill spells to make Blood Artist more relevant.

I would suggest upping your land count by 2-3 as mana screw kills the deck and it never really not want more mana to extort more or cast a huge x spell.