Don't know, I just believe San Andreas is the most overrated GTA game. The countryside was complete wasted space. The open parts of the desert was wasted space and had no purpose. The storyline was highly inconsistent. It went from this to that to another thing and back to this thing. The storyline would've been much better if it were all centered around Grove Street.
The storylines of every other GTA game was consistent. CJ was basically doing other things waiting for Sweet to get out of jail instead of focusing on the 'hood. When you look at the flaws of all the cities, you see Liberty City and say it's small and too dark (GTA III). You look at San Andreas and see it has much wasted space (Some think it's great, some don't). When you look at Vice City, I see none. I hear that Vice City is too flat but Florida has the lowest highest point above sea level of all of the United States so you have to give that a pass.