First off:
What about Primeval Titan?
That's a fantastic green mana ramping card, plus, it's big. Also Vorinclex, Voice of Hunger is a wonderful creature for doubling your mana, and shutting down your opponents.
Something else I would do, is switch out Gauntlet of Power for Caged Sun. For only ONE extra mana, it will only affect your side of the board and not everyone else too. That can be a huge advantage in a game.
Also another new card that just came out that would be useful is Craterhoof Behemoth
What about Primeval Titan?
That's a fantastic green mana ramping card, plus, it's big. Also Vorinclex, Voice of Hunger is a wonderful creature for doubling your mana, and shutting down your opponents.
Something else I would do, is switch out Gauntlet of Power for Caged Sun. For only ONE extra mana, it will only affect your side of the board and not everyone else too. That can be a huge advantage in a game.
Also another new card that just came out that would be useful is Craterhoof Behemoth