I can safely say, the allies that abandoned the server were pretty much just babies having a tantrum, the server is no harder to level on than it was in vanilla.
Yup you get ganked a lot but no more than the gankings I got while lvling to 60 as horde.
So I have seen for myself, the guys that left were just scrubs. Try it and see for yourself, It is nowhere near as bad as the allies, that literally managed to lose the game (That is supposed to be impossible), would have you believe.