Yes and no. Depends game by game, if people catch my drift.
But for the BIG game, with 4 teams, AI would be helpful to minimize the chance of 1 team being sandwiched between two other human civs.
I have set duels on Micro world, Pangaea, 60% water, 2 civs (both human), no AI... and had the two civs start 10 tiles from each other. the game setup mechanics are not tuned for this.
Then again, in another I started on an island big enough for 10 cities. It was quite comical. the guy never found me before the stack of 16 horse showed up next to his first city and... that was all she wrote