Sorry in advance for necromancing this thread, but i think the topic is still kind of relevant.
Scutariis comment about planning your expansion is neat in theory. But the concept clashes heavily with many victory conditions.
If you are expected to conquer an expansive TSE, or hold the entire mediteranean cost, you can not "plan smartly where to go". Simple as that.
And yes, you can do a work around. Use the force_diplomacy script to give some of the richest cities in the game to the enemy. So that you improve your income.....
....anyone else notice the flaw with that?