Green is worth having around for Mana dork, especially
Noble Hierarch. Being able to go T1 Noble, T2 Geist, T3
Steel of the Godhead is pretty much game over for almost any deck. green also gives
Unflinching Courage (basically extra copies of
Steel of the Godhead). You can even live the dream and go:
T1 Noble
T2 Geist
T3
Steel of the Godhead, Swing for 9 (because of exalted trigger)
T4
Unflinching Courage (or another
Steel of the Godhead, or 2 more Nobles), Swing for 11, win.
Realistically, Man dorks,
Unflinching courage,
Gavony Township, and
Dryad Arbor (to get around sacrifice effects) are the big reasons to keep green, and frankly, the possibility of a turn 2 Geist is good enough to justify green to me