I'm sorry for bumping such an old topic but I'm really interested in this deck and would like to continue the discussion.
I know he'd like to keep the deck mono green but perhaps he can replace some forests with Tropical Island or Breeding Pools and add in a few copies of Mana Leak/Stifle/Trickbind somewhere? Since the Tropical Islands and Breeding Pools are forests you can search for them with Land Grant if you need to.
I was also wondering if Soultether Golem and Seedtime would somehow fit in the deck? A Seedtime could be fun after your opponent plays an EOT Brainstorm or something similar.
Edit: Would Groundbreaker be a decent choice for this deck?
The problem to me is that you need
a. enough offensive creatures to swarm -- say ~20 -- and some alt-cc ways to play them on the first turn (such as Elvish Spirit Guide)
b. Berserk to have any chance of killing fast enough to be competitive which entails 16 pumps at a minimum (including the 4 Berserks)
c. a minimum maindeck disruption package of:
4 Root Maze
4 Leyline Of The Void
4 Chalice Of The Void
There just isn't room for all of that, even if you are playing "9 Land"