Are you set on keeping this mono-black? Even at a really budget price, something like Rally the Ancestors or Return to the Ranks would greatly increase your staying power in games. Or staying in Mono-Black you can get a lot of great consistent fueling cards like Grim Haruspex and Immortal Servitude, even ignoring pricier options like Bridge from Below. I think that the sacrifice to draw cards are overrated and not that useful because they only get you a few cards from each one, whereas a Grim Haruspex could draw you a lot more cards.

If you maybe want to make the sacrificing a little more consistent and focus more on the Bloodthrone Vampire and Rite of Consumption plan, maybe include more creatures like Myr Sire that replace themselves. Cards like Doomed Dissenter, Carrier Thrall and Sultai Emissary are all fine options and allow for two sacrifices with one creature. Maybe replace the Perilous Myr and Tattered Mummy with these options, as although those creatures do hurt the opponent, committing fully to just bloodthrone-riting someone out should make it so you don't need the extra damage. Hope this helps in some way, really like the deck!

Bloodcrazed Paladin would go nice. On a turn that you sac stuff you get a huge creature for 2 cmc.

@Rennash1- Not a bad workaround for a secondary wincon. If they remove my Bloodthrone, I can pop this out instead of Rite, and still have a board presence. Thanks man! Appreciate it!

Play hard!