Uhhhhhh... Without being completely 100% accurate and technical about all the ins and outs...
The World Rankings were taken, like, 2 years ago(?), and used to decide the pools. Back then this is when Wales had that "slump" or whatever and I think fell to 8th in the World... Or 9th.. I think Australia were 2nd, and England were 6th or there abouts... This is how this whole "pool of death" has happened.. Otherwise, I think it would be Wales in SA's group, if it was taken a year out from the WC?
edit: See above, for accuracy.