When I start the game in 1920x1080 resolution in full screen mode, the screen flickers. But, if I switch to 1600x900 and then back to 1920x1080, it works just fine. 1920x1080 also works fine if I start in windowed mode. This happens on the PTR and on live as well. I am using an aluminum MacBook with Snow Leopard.

Can you list some of your computer's spec's here, and I'd also advise that you post your issue in the Mac forums.

If you list some system specs such as video card, we can try and assist you.

Natharsis,
Can you try something that may resolve your problem.

1. Go into System Preferences
2. Select Energy Saver
3. Enable "Higher Performance over Better Battery Life"
4. Retry your bug.

I'm told that the Macbook Pro that you "might" have has a hybrid type of graphics that, if not set to Higher Performance, will cause issues with WoW launching.

Well, in that case, I think the only other advice I can give you is to take this issue to the Mac forum. They may know what you can do to resolve your problem.