Inspired by the adjacency bonuses Brad mentioned in one of the beta 2 threads, I'd like to propose a much less micro-intensive suggestion: automatic city specializations.

Based on whatever type of building is most prevalent in a particular community, you'd receive a % bonus in the production of said field, complete with swanky icon to show you what you should concentrate on in the future. As an example, if you have a lot of schools and other research buildings, you get a 100-150% bonus in the production of research points in that city, depending on how many you had. Here's a list!

Agricultural, food bonus
Enchanted, essense bonus
Frisky, population growth bonus
Glamourous, prestige bonus
Industrial, materials bonus
Intelligent, research bonus
Rich, money bonus
Stronghold, unit time reduction
And so on.

Usage in a tool-tip/city description: Palatka is a Glamourous City and receives a 120% bonus in prestige.

The advantage being you wouldn't have to toggle anything or set anything or design anything in a specific place; it'd all be done automatically so you could concentrate on other things.