Okay, so with the new deck I've taken a look and I really think you're too scattered. Normally the best decks figure out 1-3 solid combos and then build around them. When you have 25 distinct cards in a 60 card deck, that means you're not likely to see the same card very often (which is problematic if you need a particular pairing to win the game). You've found some interesting cards that I wasn't aware of that could work wonders with some of the newer cards that have come out with AVR.
First off, you stated a fear that you have too few creatures. I've seen some really good decks that can operate off of that many or fewer, it's just a question of how they're utilized and how you envision winning the game. Given the current layout of your deck, I'm not seeing a clear win condition, just a lot of removal and countering to bother your opponent. In a typical game, how do you envision winning? The largest creature you have is a 4/4. Beyond that the only real offensive weapon I'm seeing is Control Magic. What if they counter Control Magic or otherwise deal with Ashling? Then what?
So here are some suggestions. I'll avoid any cards that are too pricey as you never want to drop $50 for a deck you hate to play.
1) You can work Nekrataal via flickering (or briefly exiling and then returning to play). So I would advise some Ghostly Flicker, Nephalia Smuggler, or perhaps best of all Deadeye Navigator or Conjurer's Closet. In any of those cases you can flicker Nekrataal and when he returns to play his ability triggers again, meaning you're making them drop their creatures. This would also require you to pick up another Nekrataal or two.
2) Flickering will also work with Gravedigger and Parasitic Strix. This means you could also drop down to one or two Gravedigger (as a four drop 2/2 isn't very good) and put the added Strixes in there.
3) Since the main thing going here is creature removal, Blood Artist would be good fun here. So would Deathgreeter. Then you're getting even more benefit out of their creatures dying.
4) You should work around Ashling, the Extinguisher as a central piece. If you're really out to make them lose all of their defenses, you need her to do some work. So you could pair her with Artful Dodge to slide on through their defenses for a hit (and causing them to drop their favorite creature). You could also work with Wingcrafter to give Ashling flight to make it that much more threatening.
5) For the spells you have, you really don't need that much counter magic. To the extent you have those in there, you should increase the number of spells up from one to two or three. So, more specifically, I'd lose the Unsummon, Oppressive Will, Remove Soul, Mana Leak (I know that's MTG blasphemy) and Snakeform. You could then add more Boomerang. Sitting with four Counterspell and four Cancel should be sufficient to disrupt anyone's plans, further, unlike Mana Leak those two can't simply be paid for to negate.
7) Bone Splinters works as long as you're ready/willing to lose a creature too. That's fine if you want to work with Raise Dead or Gravedigger. If that's the case, I'd use something like Tragic Slip over the normal black removal spells, as it doesn't have the "nonblack" or "nonartifact" requirements those do.
Anyway, the resulting deck would look something like this:
http://deckbox.org/sets/182559
The best part, nothing I added is more than $0.50 with a TOTAL deck value of less than $20.
As always, these are just suggestions, but I'd wager you could get some pretty consistent play out of this and it would be frustrating as hell to play against . Best of luck!