Sammystorm

You also should run priests of urabrask because the three mana they give you can combo into a bushwacker or a hero or another priest or pretty much anything in your deck.

I also have seen Kuldotha Phoenix run well in this style. Also Koth seems to fit in well.
However those cards do provide dead drops in the early game so I guess it is what you are going for in the deck.

I would say toss in some fork bolts. I like to be able to split the damage. Pyroclasm is really good at stalling the faster decks and I would side it.

Dispatch is only good if you can get metalcraft and he doesn't have much capabilities to get metalcraft.

These kinds of decks are scary fast. However they still are vulnerable to marrow shards, mental missteps, pyroclasm, and slagstorm.

That being said: Have you considered running Hero of Oxid Ridge?

You should tell me what you think of my deck http://www.mtgvault.com/ViewDeck.aspx?DeckID=184666 its my blue deck titled nasty life switch.

Instead of scry put in fetch lands such as evolving wilds and Terramorphic expanse.

My favorite art is Mental Misstep.

Scrying for two does not give you that much dependability instead you should add two more basic lands.

My main problem is that you have nothing to protect melira and you have no counter spells to protect phyrexian unlife. i would say run dark steel plate and whispersilk cloak as well as some mana leaks.

What about mutagenic Growth? Thats a great boost card!

Seeing as you are going for infect you should consider putting in Triumph of the Hordes. It is a 2 colorless 2 green sorcery that gives your creatures +1/+1 Infect and trample until the end of the turn.

I would use Torpor Orb because it makes it so that the only way around it is with artifact destruction. With the Leonin Arbiter people will play around having to pay two extra mana for their cawblade or deciever exarch. The other thing is that this block is so creature heavy that people tend to run kill spills over artifact destruction.

The problem I have with this deck is how much little removal you have. The Dispatch is good but only if you have metal craft. What happens if someone pulls a Kuldatha rebirth on you turn one? You won't have much speed to compete with some of the faster decks making it hard to run this one.

Instead of leonin Arbiter I would side Torpor Orb. it is a 2 cost artifact that make so abilities don't activate when creatures enter the battlefield. The nice thing about it is that it shuts down both Deciever Exarch/Splinter Twin and Caw blade combos.

He is right here. The amount of green mana you have available will limit you severely. For this deck to work you will need green mana for your first three turns to get the ramp. The blue is second most important because of counters the white should be be very limited.

I would say 5 forest, 3 islands, 2 plains, 2 glacial fortress, 4 Razorverge Thicket, 3 Seachrome Coast, and 4 Sunpetal Grove.

An edit: You are running too many creatures to run Mass Polymorph. Maybe some wing splicers because it gives you two creatures for 4. Also try to get some blockers with reach or flying.

I honestly would make this deck Green Black.
With Green you get the mana ramp which is looking good in this deck.

With black you get great spot removal like quag sickness, doomblade, and go for the throat. With black you also get search power with Diabolic Tutor. In this type of deck Getting what you need right away is key.

If your attached to the blue Praetor you can run it with out blue mana because the goal is to exile it anyway.

If your attached to blue I would consider running Mass Polymorph. It is a little costly but it is cheaper then Praetors.

Also this deck must absolutely have 4 Karns. This deck is based on Karn and will absolutely flop if Karn does not get out. So limiting your chances of drawing it by only putting in 2 makes you less likely to win.

This is a pretty sweet deck!

I personally favor the White Green Blue Golems with Vensor the Sojourner as my Planeswalker.

If you want to run the precursor Golem I would really consider running Asceticism. That way you have a 4 drop that can regenerate your splicers and Golems and gives them shroud.

I personally am not a big fan of Maul Splicer because she costs 7. In this case I probably would run more blade Splicers and Vital Splicers.

Other then that this deck seems like a very solid build.