There is a solution if you are willing to edit the rules of the game. I too thought that the incredible corruption was ruining the game, so I went into the editor, and under improvements there are a whole bunch of boxes you can click for each one. One of the options is "reduce corruption" or something like that. I clicked this box for things like the temple, cathedral, library, university, bank, etc. What this does is, the more of these units you build in a city, the less corrupt it is. So over time, as you build more improvements, your outlying cities become useful. And it helps the AI as much as you, so it's not really cheating. One thing it does do is some civilizations end up with a ridiculous amount of money, and technology probably moves faster too.