Surrender

Sometimes you get to a point in a game when you know you've won, the AI could probably make an educated guess that you've won, but you have to keep playing to complete the game. Advanced Tactics addresses this issue well as it is not necessary to capture every city in order to get the required victory points to win the game. One disadvantage of the Advanced Tactics method is that the player knows exactly what they need to win and can cynically take easy cities to get the required victory points. Additionally, you don't get the pleasure of seeing the entire world under your flag.

An alternative to the Advanced Tactics method, would be to have the AI surrender when it is clear that they can't win. The AI's territory and cities transfer to you (but not their units).