I cant believe this was over looked!
Seriously I cant believe sanitation research and hospitals were over looked! Granted they dont need to be super complex but there should be away to keep cities clean. For example having a sewer system/aqueducts increase prestige as the city is clean and people want to live in clean cities. Hospitals can also increase a city's prestige as well and should offer a tangible benefit like increased unit health when stationed in a city with a hospital.
Of course this does not need to be overly complex since researching various advanced medical concepts is beyond the scope of this game, however there should be basic health and hygiene building/research.