I recently played in a Draft tourney and got Assault Formation as my initial card. I decided to build a draft deck around it and it turned out amazing. I got to thinking, how can I build a Modern deck around it? What you have is the result...
Assault Formation is the key card to this deck... Since Assault Formation deals damage based off creature toughness, why not add the toughest green card around: Tree of Redemption. For a mere 4 CMC, you get a 13/13 Defender, that can attack for 1 green mana. Additionally, you can use this card to crank up your life total, if you take an early beating. Wall of Roots is a great option for mana ramp in this deck. Not only does it start out at 0/5, but it pop's off mana without tapping. Juvenile Gloomwidow is great for the reach ability and it's wither is a great bonus in a deck like this. Updraft Elemental makes a nice fit here for a flier and Wavecrash Triton is another great fit with an tap ability that combo's with the instants and enchantments. I threw in one copy of Sigiled Starfish for the scry ability.
For back end buffs, I went with Tower Defense and the extremely efficient Triton Tactics. I also added Vines of Vastwood for instant hexproof, which can be kicked to crank up +4/+4. And don't forget that Assault Formation has a buff ability as well.
I went with the budget dual lands in Hinterland Harbor, and I tossed in a Simic Growth Chamber since the deck can be mana intesnive. I added one copy of Rogue's Passage for an additional unblockable mechanism.
For control, I went with the cheap Negate. I then stumbled upon Muddle the Mixture. What makes this card perfect is its Transmute ability to tutor for Assault Formation, or any other of the 2 CMC cards in the deck. Otherwise, its a decent Counterspell against Instant and Sorcery cards.
For card draw, I went with Telling Time and Foresee.
Aqueous Form will get you past blockers and give you a scry ability.
Nissa, Steward of Elements is great here. You can cast her for X=2, use her +2 to scry 2, and then her 0 ability from there on out, since no permanent is over 4. Huatli, the Sun's Heart was recently released, so I threw in a copy as a back-up to Assault Formation, and also for the life gain.
I round out with two copies of Swiftfoot Boots. It's mostly for the Hexproof, but the haste can be a nice added bonus. And its funny to kill your opponent with a giant tree wearing boots.... haha.
