While im at it i want to say that this statement is false. I know many shadowpriests, including myself that live in Australia and all do amazing dps, i cannot speak for all of them but if you look at the oceanic realms and then go to the WMO shadowpriest dps rankings (found here -
http://www.wowmeteronline.com/rank/clazz/dps/pri/9/6/3) you will see a large number are from Oceanic servers. Incase you dont know oceanic servers i would do a CTRL + F on Barthilas, Frostmourne and Dreadmaul. There are some oceanic shadowpriests that do very good dps with terrible MS.