No Kingpin's Pet? Could fit in well. might want to consider more Vizkopa Guildmage because you have the potential to gain a lot of life, and for just three mana that means lots of over the top damage.

I've been considering a change of Basilica Guards I dont find they are needed after I get a High Priest of Penance or two on the board so I might put the pets in place of the guards. Only reason I havent added more Vizkopa Guildmage is Ive found them to be a big target for removal. I've been trying to focus more towards extorting but the combo of Vizkopa Guildmage and Exquisite Blood being a one lifegain win just seems like fun.

Thanks for the comment Minister_Crabtree

I'm not sure about Crypt Ghast in this deck - there doesn't seem to be a great need for ramp here, and by the time you have the mana to play it, you can play most of your deck anyway. He's really just an expensive 2/2. I would consider Syndic of Tithes instead - 2/2 for cmc 2 and an extort trigger into the bargain. I'm also not sure about Treasury Thrull - at 6 cmc he's very expensive unless you can trigger a win condition with the ability. Personally, my favourite big fat Orzhov creature is Alms Beast - 6/6 for 4 cmc, dirt cheap if you need to buy/trade for them and can cause a lot of damage if you stick Gift of Orzhova on them and use the 2nd Vizkopa Guildmage ability.

Crypt Ghast is there to double your mana so that extort basically gets cast with each spell for free. Or to make that 6 drop a 3 drop the next turn. Plus he has an extort on him as well, he can help turn extort into a wincon. I'm not likely to take him out.

The Treasury Thrull may be one that gets swapped with the Alms Beast I do like the 4 drop 6/6 aspect. Only thing that worries me is the giving lifegain to the blocking creature.