New expansion, new map
In Wrath of the Lich King, we'll get a new continent, new talents, a new class, a new profession, and probably lots of things we don't even know about yet. However, it looks like some of the old is also changing. Inspired by a post over at Casual WoW, the above image shows the WotLK map with outlines from the current live map superimposed in blue. So what's changed?
Kalimdor changed in shape significantly. No longer looking quite so much like a penguin, it now has a more crescent-shaped profile.
Two new islands off the southwest coast of the Eastern Kingdoms.
New bit of land north of Westfall, west of Stormwind on the west coast of EK.
Islands Northwest of Tirisfal removed, and two small ones added north of Scarlet Monestary [thanks, Captain Tonga]
Why do you think these changes were made? Theorize away. It looks like mostly unreachable areas that were removed, but I can't imagine what they're going to do with that new chunk of land near Stormwind. Of course, this is just artwork, and may not correspond that closely to actual in-game geography, but I bet something is going on there.