It was clearly drawn on two pieces of A4 stuck on top of one another, and looks a bit weird as a result whenever larger-scale maps of the rest of the world are put together. The HBO maps actually look a bit more naturalistic (they squash the continent a little bit to make it less square). The square world thing is rather common in fantasy - Tolkien, Jordan and Bakker all suffer from it - but the vertical orientation of Westeros seems to accentuate it. I actually quite like Erikson's take of having fully-drawn out continents and then having the action take place in a corner of them regardless of how neat that is on the map.

The topography also isn't hugely realistic, at least not any more than most other fantasy worlds. Dorne looks like it's a seprate subcontinent that's collided with Westeros, forming the Red Mountains, which is fine, but the Vale of Arryn is really odd. The mountain-building processes there look strange and clearly GRRM wasn't thinking plate tectonics when he came up with it.

It's also worth reiterating that the map is a rough speculative thing thrown together based on GRRM's descriptions in the book. We have to wait a while to see the real deal. Though that doesn't mean it'll be any better. I really don't like Essos's shape compared to Westeros, I feel it should really be a big, bulky continent like Eurasia rather than this odd thin thing.