Managing the Roman Empire is no easy task, but somebody's got to do it. And in Caesar IV that somebody is you. After an eight year hiatus, the classic city-building franchise is back, in all of its micro-managing glory.
Limitations on city size and esthetic requirements are the two biggest obstacles (outside of the economy) that any budding governor is going to face. Just as in real life, real estate in Caesar IV is a limited resource and how well you plan out your city can easily make or break a mission.
There's nothing more annoying than having to tear down a section and rebuild it simply because it wasn't an efficient use of space the first time around. Aesthetics are important because no one wants to live in an industrial park, not even the lowly plebs. Segregating the housing from the working parts of the city is a necessity if you want to attract citizens.