Skarrg, the Rage Pits.
I don't think that trampling over creatures is a big problem unless you are against mono TNN, you already have punishing fire to clean up most of the board and with that creature base your creatures should be significantly bigger than anything your opponent is playing. I like the manabase being better (although I think I would -1 plains, and +1 dual since you are mostly green based anyways) but my only gripe with the deck is the lack of CA engines now that Confidant/Lili aren't there.
Shifting away from black is perfectly reasonable but I think that you gotta make up for the CA that you are losing. Niklas's Bant list he posted a while he does this by adding Jaces, Cliques, increasing the number of punishing fires and playing some Dacks in the board. I feel like you can easily go up to 4 GSZ here since your creature base is entirely green sunable. The list looks like very neat though, it reminds me a lot of punishing maverick.