Offalsnout is awesome. There's no way I'm playing something like Relic of Progenitus or Tormod's Crypt. I like to remove specific cards rather than entire graveyards, mainly to be less of a hoser. Shred Memory was the other consideration. Either way I shape games so that the smaller bodies are a little more relevant, thanks to equipment; if he ends up just being a Coffin Purge on a guy, he's doing his part anyways. Come on, it's Offalsnout!
I'd prefer to use Bone Shredder due to nostalgia, I have used Shriekmaw in the past. Shriekmaw costs one less to recur with Genesis for the Evoke. I have a foil Maw to switch with my foil Shredder if I ever wanted to go back, which I might.
I also originally had Barter in Blood, but, there never was there a time I could get full value out of it and usually ended up being another Innocent Blood, I'm not paying 2BB for Innocent Blood, if I need something else I tutor for it
I decided against Decree of Pain months ago. It was cut simply because this deck really doesn't require more than a few wrath effects. Usually I would find myself drawing a wrath when I didn't need it. Then again, at the time I was also running Plague Wind as well. The draw is nice, but most times I found myself discarding things I didn't want to get rid of, despite some recursion, I would prefer to obtain draws from blue sources. I love the card though and it's going in Oros, but I just didn't see it fitting in Vorosh anymore. I'd rather be making threats than removing them.
This deck works out to be more mid range than anything else, so finding the balance is what I was seeking. A quickly Tinkered Sundering Titan or a very hard to beat late game is usually good enough for a W. Its a dangerous pile of (mostly) foil goodness.