Yea the wow installer is horrible. You need double or more free space to the size of your game for the install. You download 6 gigs of patches, then they copy the whole game while overwriting the old one. Don't know why they can't just patch one file at a time and need oh say 10mb free space?
Munching On: Archeage, SAO Vita, Tales of Xallia 1/2.