Let's assume a set of basic features that let's you get closeish to the 8 bit pokemon games. What would be simpler to create?
Large city that has a series of dungeons/gyms? Example. City championship thing where you have to get glyphs/crests from a set number of gyms before you can participate. Additionally you can go into city park, an under city that leads to a set of caves.
Series of smaller two or three building clusters in a large world you explore.
Or is it more once the features are there the world size and configuration doesn't matter?