Most people I know use WSAD because they don't have to move the keyboard to play. I use the arrow keys in all of the Battlefield games and have just as many key mappings surrounding them. I've never been slowed down by reaching for the keys because I'm so used to them. I do use WSAD for WoW, simply because there's not many required keys to map besides jump. I would switch to WSAD for Battlefield 2, but I've been using the same key layout for every BF game in the past 4 years and it would take me months (literally) to get used to a new layout. I don't wanna go through the annoyance of dying due to the keys being remapped so I've just left it the same.
