Actually all bosses were tested on the PTR in heroic mode except Ragnaros. Whether or not they downed those bosses I don't know, but they had a fair amount of time to learn the fight and make some strategies. Personally I don't care too much as to who wins, but if I had to root for someone I am rooting for a US guild. I just don't want there to be bugs that cause people to cheat WFs anymore.