On the surface, from a very long distance, yes, Monstropolis and the Monsters Inc building are supposed to look like an average, "boring" modern city.
But when you get closer and see things on street-level, you see all the crazy things that are different in a city populated with monsters of wildly different sizes and shapes (there's a whole sequence at the beginning of the film emphasizing this very idea). What makes the city interesting is how it's different than what we are familiar with.
This is also, much to your apparent bafflement, what some people are excited about when it comes to the entire land. Presumably, this won't simply be "normal cityscape and buildings that could be anywhere in the country" (unlike, say, Grand Ave., ahem). This land will (again, presumably) be filled with many little details and visual gags befitting a city of monsters.
It may not be something you personally are interested in, but it works great as a setting for a mini-land with a couple of attractions and restaurant(s).