I've been thinking (I probably know the answer), why no dark confidants or Phyrexian Obliberator?

Instead of the Deathrite Shaman/Death's Shadow. But indeed, an extra one drop is handy that can control the graveyard, the BoB could give you more card advantage, but so does the draw 4 cards, instantly. Plus hitting Soul spikes hurt. So I get why you don't include BoB.

But Phryrexian Obliberator, could that be an option? Instead of the Death's Shadow? I know that DS has a lot of synergie with the rest of the deck, but since you run mostly basics, less scared of wastes and play dark ritual and deathrite shaman, you can easily put that beast down in turn 2 or 3. STP kills it (free from Abrupt Decay though) and if STP hits DS, at least you go back to 13 life. So I see value in both.

Just a thought that he might be able to see play here.