N810

I generally include only a few copies of non-essential high cost cards, since they are only useful later in the game, when you are more likely to draw them.
lower cost cards I include more of to insure you have something to cast early on.
On the other hand I will include four of any card that is essential for the deck no matter the cost like Mechanized Production.

Flameshadow Conjuring Might be a useful addition..?
It combos nicely with the free creatures and card drawing,

+12/+12
(+1/+1 for each Other Creature of the same type)

Maybe add one copy of Rogue's Passage ?

It also works for your opponent, so beware.
http://tappedout.net/mtg-questions/how-does-coat-of-arms-work/

Maybe some tribal enhancing artifacts ?
Examples:

Herald's Horn
Vanquisher's Banner
Obelisk of Urd
Coat of Arms

... fine, I misunderstood earlier.

http://www.mtgvault.com/cards/search/?q=zombie+master&searchtype=name&ps=20

oh, I was just thinking, since you have Urborg, Tomb of Yawgmoth, making all lands swamps, maybe throw in Zombie Master to give al of your zombies swamp walk.

Seems a lot better, you will probably need to playtest it a bunch to further refine it.

Compare Shivan Wumpus to repeatable land destruction cards like Earth Rift or Icefall and it starts looking better.

Primal Vigor + Mycoloth .... Profit ?

Just drop the less essential cards from 4 copies to 2 or 3.

Example: (60 cards)

//Creature (7)
2 Gray Merchant of Asphodel
3 Tattered Mummy
2 Wayward Servant

//Enchantment (14)
2 Anointed Procession
3 Black Market
3 Endless Ranks of the Dead
3 Quest for the Gravelord
3 Swarm Intelligence

//Instant (4)
4 Cabal Ritual

//Planeswalker (2)
1 Liliana, Death's Majesty
1 Liliana, the Last Hope

//Sorcery (7)
3 Army of the Damned
2 Dark Salvation
2 From Under the Floorboards

//Land (26)
4 Island
4 Plains
16 Swamp
2 Urborg, Tomb of Yawgmoth

Wayward Servant is a good choice the other one isn't bad either, the loss of life should give opponents pause.
yea, now you have the hard choices oh thinning your deck a bit closer to 60 cards,
I usually start by cutting down on the copies of my high casting cost cards.

I feel like it needs a cheep 1 or 2 drop zombie in there somewhere.
Just to slow down your opponents creatures for a couple of turns.

Well it's usually better... But the one thing it doesn't do is also have your opponents discard their hand as well.
and that speeds up the mill quite a bit by also comboing with Fraying Sanity.

But it is worth the sideboard, maybe to trade out with some of the walls occasionally.

You will just have to add a trample creature instead, oh and one enchantment you may want to consider is "Venom" basically it's an old skool form of a death touch aura basically doing what the Basilisk and Cockatrice do already. It might be fun to drop on the archers.

Originally I had wall of kelp in there because of card advantage, as it can keep making more kelp walls for (u)(u).
But I will admit Guard Gomazoa is probably a better thematic fit.

In truth, the wall are really of little importance, and could be easily be swapped out with other cheep blue creatures,
with little effect on the decks performance. Anyway, thanks for the recommendation and the critique. :)

Maybe throw in some budget Madness cards, since you are going to be discarding them anyway.
http://www.mtgvault.com/cards/search/?q=MADNESS&searchtype=text&c=u,b&ps=20

Hmmm... Shaman of the Pack definitely makes this stand out from the usual elf deck.