Looks good. It seems like you're going to be pretty vulnerable to decks with flying. Have you considered
Magmatic Chasm for a sideboard card? It would prevent opponents from blocking so you could swing in for damage unimpeded and also
serve to potentially
lure flying creatures down and destroy them.
Lightning Axe or
Burn From Within in the sideboard so you can just fry them.
I would probably play at least one or two more
Sin Prodder since it has menace and you have some cards that let you pull cards from the graveyard. Although if an opponent has you put a card in the graveyard as part of
Sin Prodder's ability can you cast it at it's madness cost? The card text doesn't say "discard", just to put the card in the graveyard so I'm not entirely sure about madness.
Just a thought but if you used some buffs like
Grotesque Mutation,
Brute Strength,
Trumpet Blast (I know those last two are not SOI) with cards like
Sin Prodder or
Hulking Devil then you can go really aggro on your opponents.
Trumpet Blast would also be great with your little devil token army.
Westvale Abbey might be kind of a cool land since you are generating Devil tokens, you could always sacrifice them for
Ormendahl, Profane Prince. Although you probably intend to sacrifice them to
Blazing Hellhound.
Just my two cents. It seems hard to give you advice when you're the one always helping others so I hope it was decent!