My suggestions:


Heartless summoning really only helps you cast your ONE pontiff, and in the process it prevents you from casting tithe drinker. Try and find something else if you can. 

I'd replace pillory of sleepless and/or executioner's swing wither either mortify or revoke existence. These are solid removal spells at the same mana cost. I would also suggest replacing smite with something different, such as celestial flare.


You have SO many lands, you should flip the numbers: 36 nonland, 24 land.


For ramp (instead of heartless summoning) I would suggest using crypt ghast, it doubles mana produced by your swamps, and it has extort as a bonus. 


Finally, I'd suggest increasing the numbers of some cards you have here to 4. You're not super likely to draw a card if you only have 1 of it in there, which isn't desireable if you depend on that card.