Sanguine Bond is getting cut purely based on cmc and the fact that the ability is on a lot of different cards. With
Vito, Thorn of the Dusk Rose being a 3 cmc version, it makes much more sense to me.
Exquisite Blood will definitley make it in the list when I can find a copy, it is rather pricey at the moment.
Blood Artist and
Blood Seeker will probably get cut later as the deck evovles.
High Priest of Penance is a nice trap card, you block with it and vindicate something. I'm still on the fence if I want to use the soul sisters here.
Well of Lost Dreams might come in as additional card draw.
Bolas's Citadel does work, and even more so with
Necropotence to filter out lands and unwanted cards, which in turn would make
Aetherflux Reservoir great as well.
Notably, I'm missing all the good X spells. Which I need to evaluate and decided which are a good fit after I see what is working in the deck and what is not.
End of the day though, there are a lot of good cards to be used, and I guess it's all about the direction I take with the deck. With all these options available it's hard to decide which tax, gain and drain to use and how many of each. Trial and error for sure. But I do appreciate your suggestions.