The basic idea of this deck is to flood the battlefield with tokens... not just under your control, but under the control of your opponents as well. With Soul Warden and Suture Priest, this can only benefit you. Since every creature your opponent gains does damage, we'll be giving lots of tokens to your opponents.
Your opponent wants to use Detention Sphere or Oblivion Ring on your Suture Priest? That's fine. We'll use Aura Mutation to get back your Suture Priest and gain life and tokens simultaneously.
Any artifacts that might hurt you? Artifact Mutation
Any huge creatures that can hurt you? Mercy Killing
And, when you finally have enough mana, just pull out your Dovescape and now your opponent can't even cast non-creatures spells without doing damage to themselves-equal to the CMC of that spell!
We've got creatures that will take advantage of our Suture Priest, like Akroan Horse. We are basically converting Varchild's War-Riders's cumulative upkeep to read "do one damage to opponent for each time counter on Varchild's War-Riders. We've got artifacts that give away tokens: Genesis Chamber. Even our land is doing damage by donating a spirit (non-flying, btw): Forbidden Orchard.
The amount of tokens your opponent now has shouldn't be a problem, because we should have far more tokens. And if we don't, let them do damage: Darien, King of Kjeldor will give you that many tokens and then you'll gain at least that amount of life back, depending on how many Suture Priest and Soul Warden cards you have in play.
We've got plenty of ways to get our own tokens:
Akroan Horse
Assemble the Legion
Tukatongue Thallid
City of Brass
+
Darien, King of Kjeldor
(any pain lands or Manabarbs will work for that matter)
Repeated uses of Mycoloth to get larger and larger masses of Saproling tokens.
Plus, we could always use Mercy Killing on our own creatures if desperate.
On top of it all, Tolsimir Wolfblood makes all our tokens at least +1/+1, and we can tap it to add a token.
Summary of tokens in play:
White Soldier - Akroan Horse, Darien, King of Kjeldor
Saproling - Artifact Mutation, Aura Mutation, Mycoloth, Tukatongue Thallid
Red/White Soldier - Assemble the Legion
Blue/White Bird - Dovescape
Colorless Spirit - Forbidden Orchard
Myr - Genesis Chamber
Green/White Elf Warrior - Mercy Killing
Voja, White/Green Legendary Wolf - Tolsimir Wolfblood
Red Survivor? - Varchild's War-Riders
TOKEN FLOOD!!!