For a while now there have been rumours from the WCG committee, telling us that professional Korean players passively protested against the map pool which was used in the official preliminaries.

The reason was the absence of the WCG maps amongst those which were played in the Korean proleagues. Therefore professional players couldn't have as much practice on the "old" maps.

Whether WCG agreed to help the South Koreans or they're just updating the map pool, new maps are being introduced from the proleagues and the map pool now likes like this:

Blue Storm
Troy
Othello
Andromeda

Source: GosuGamers