I've been brewing for post gatecrash and this is what I've come up with so far, it's still a bit rough around the edges but it's been pretty strong in testing.
The base came from the green white list I was running before GTC and after a saw Zegana I though that this could defiantly be a thing. Adding blue allows access to detention sphere and side boarded verdicts which are what I really feel that G/W needed as things like entreat could really blow you out.
Blue also gives us access to drawing which I feel was another weak point of G/W. I see a lot of decks running 4 sphinx's revelation but I feel that it takes up to many slots in this deck and I think you can get away with 2. Same with Snapcaster, the majority of the time you are going to be reoccurring charms which has won me a few games but again 4 feels clunky as it's just a 2/1 but 2 feels about right.
I'm still unsure about mystic genesis but the more I have been testing with it the more I like it. I feel it can quickly tilt things to your favor when it goes off and with the amount of flash/instants/gavony type effects you don't feel so bad about them saying draw and go after you have left mana up.
Lemme know what you think.