Battle for Middle Earth did that quite well. You could play on a ladder system that paired you up against people with a similar win/loss ratio. A friend and I u

Battle for Middle Earth did that quite well. You could play on a ladder system that paired you up against people with a similar win/loss ratio. A friend and I used to play 2v2 quite a lot. We got to the point where we could comfortably beat 6 AIs and we were OK against people with a little online experience. Occasionally we played against serious people from the forums and got thoroughly destroyed. It was fun, but beyond casual battles it became too much like exploitation of the engine - e.g. having to destroy farms yourself because you didn't want to give the enemy units experience.