I know you want it to cut out the ravnica block but if you want to optimize the deck in the current meta (because people will still use ravnica on you), then you should ditch the stab wounds and put
underworld connections in their place. I'm not sure how i feel about
nightmare... it's a great creature that will definitely get damage through with flying but i think your deck should put desecration demons in it's place due to the cheap cost. its a scary turn 4 threat that must be answered. The rest of your creature selection looks good besides the
spiteful returned... they're just too expensive for the abilitys they offer. I would replace them with Child of the Night (youll appreciate the
lifelink due to your deck's lifeloss cards).
Also replace
hall of triumph with
whip of erebos... the effect of the whip allows you to
smash in damage with creatures from the graveyard while boosting your own life.. its a very powerful tool.
Get rid of the crippling blights for a full playset of
ulcerate. I would also consider adding
hero's downfall,
devour flesh, and/or doomblades/dark betrayals. removal is very important.
Lastly, add one or two lands (preferably some scry lands like
temple of deceit/
silence