i would take out the Bile Blight for the main and put it to side board (if your really set on having the card), and replace the drown in sorrow. the reason being that the only matchups that you will need it on game 1 is splinter twin and even then the creatures generally will still live becaue thier main targets to copy are already out of bolt range. AND they typically board it out on game 2 and go to a control/burn build. or the other deck is B/W tokens and they do run many multiples of thier tokens so its a wide variety for targets. i would go with the instant speed discard or a straight up kill spell such as Slaughter Pact if your really worried about those matchups in the main board. i would also condider not running the darkmore salvages and put in fetches such as Marsh Flats, to "thin" your deck out, in addition to this i would up the land count to at least 19 preferably 20 so that your curve is more consistant, yes you have a low curve but you need the land to cast anything and on turn 3 if your stuck with 1 land, you look like an ass. if the fetches are too expensive for you i would then consider running Urborg, Tomb of Yawgmoth so that your Mutavaults tap for colored mana. and help out Mire's Toll as well. i understand that the salvages are there for the Raven's Crime "soft lock" but you need to be drawing cards in order for you to keep getting the salvage back and that mills your deck reducing your recources. the extra land will help keep the crime coming back and make "crappy draws" worth while such as when you have 4 land on turn 5 and are pretty set on lands they become crime fodder. i understand the want for so many Extirpate effects but would stick with only one version. my preference is the extraction in that its in essance a 0 cost spell. and would then sub in damnation for the wrath effects that i feel you are desiring so much. if not that i would consider Killing Wave for a wrath against such decks as B/W tokens. oh and a fun lock out for really grindy games consider running Crucible of Worlds for the Ghost Quarter lock. kina mean especially agains the control decks that really rely on their mana base to typically finish the deal, such as Celestial Colonnade. i like the improvements so far.... keep it up!

Mutilate is a good alternative to damnation if you need a sweeper. mono red puts out alot that discard cant really touch.

I like Necrogen Mists over Dark Deal.

How has Waste Not performed for you? I found the added benefit didn't outweigh what I had to remove to get it to play.

Necrogen Mists was originally in here but I took it out. Waste Not, for me, has been more of an overkill. People hate it as if it were planeswalker in enchantment form. Not as easy to remove, to boot.

What were you removing to include it?

It seem to me that you can have really hard time vs an aggro deck, I will put in more creature hate cards. Let assume you are facing a tharmo: is is in play on turn 2, nothing you can do about it, and will be out of Mutilate, Bile Blight, and Drown in Sorrow, cause you make him discards. Your only hope is a Smallpox.. Ok you can make him discards it in turn one, but an aggro will have other threats. I have a rack (well, more focused on rats) deck too, so this is my experience so far.

Also, if you have suggestion, I will appreciate it: Rats, rats, rats! Gnawed to death!

i would up the land count to at least 20 for the Raven's Crime, you do have the Dakmor Salvage but your milling your resources that may be needed, plus your ratio will be more consistent. i would take out the Bile Blight for the lands, and replace the Drown in Sorrow in your sideboard with them. -2/-2 isn't going to do a lot against aggro decks.... that's all i have for now.