Lets say your playling forces of light, and on the server waiting for a game are 2 other light players and one dark player. The server will then match up a 3v3 with the dark player getting two AI team mates. The dark player can't very well fight you all, and i don't panth supports 1v1.....ive never seen it anyway.

You just need to luck out and happen to be playing when there are plenty of players on both teams looking for a game.

What difficulty is the AI set at? Nightmare I'm guessing? Or is it based on rankings?

It seems a necessity to have AI in pantheon, while you may prefer to wait it out for real players, other people would probably rather just play. Like when I have an hour or less to get a game in, I don't want to wait.

A better solution I've been thinking about would be to balance the matchups.  So, rather than have 3 real players vs 1 plus 2 AI, have the matchmaking service balance it to be 1 real player on each side with 2 AI each.  That prevents the obvious waiting around just to have the other team concede immediately, plus games balanced that way are still playable and can be fun.

This is correct.