I've created a world before (East Haven) that was really my novice attempt of making a small world (at the time, it was pretty good I thought.) After buying a few EPs and playing the worlds there, I dislike all of them. I'm less about how the world looks as far as hills and all that and more about efficiency. In The Sims 2, the worlds were flat and gridded and were fun because if you ever bought an EP, you weren't limited by hills, mountains, etc. That's what New Manchester is for me. Perhaps others of you are interested in a flat world? If so, I'm in the process of making one.
Don't get me wrong - I want my world to look good! I just think that the hills and mountains in current worlds aren't necessary to do so and even limiting in a way. I'll post photos as I progress, but its barely anything right now.