Meh. There are more communities on other servers for example:
Vabbi - 4chan/vg, Rock Paper Shotgun
Fissure of Woe - SomethingAwful, TKOT
We'd be better off joining them imo. Less chance of us accidentally stumbling upon some moon rune speaking server which we all have to migrate from down the line. I'd rather jump on with SA or RPS as they are usually rather polite and helpful.
My concern here is that WvW has a limit of around 650 players. Being on a server with another large community increases the chances that they will be squatting in WvW when GAFGuild wishes to play.
We're planning to discuss it in the near future, but for the sake of the Beta and to avoid confusion, NA GAF members should be on Henge of Denravi, EU members on Jade Sea. This is ONLY for the Beta, folks.
I think we'd be better off on Fissure of Woe with SA, we're both closed communities and are rather polite. There is less chance of a catastrophic failure then compared to Vabbi which might be full of morons from 4chan.
In my experience, Kel'Thuzad was a bloated mess in WoW thanks to Goonsquad and the numerous groups that followed them out of admiration / opposition. It's queue times were always the worst.