I have suggested this several times, and yes, there is a simple solution to this issue.
In Pantheon/Skirmish, the players you are connecting to should just have their names as "Player 1" "Player 2" "Player 3" "Player 4" etc etc. People will not be able to tell who they are playing with, until the game has actually begun.
That won't solve anything. A premade guy will just quit the match then when he quickly discovers that he isn't with his buddy. This verification would be done even more quickly on voicechat, which a premade would likely be on.
Buddy A: I'm loading up a match on Zikurat right now.
Buddy B: I'm still on queue...
Buddy A: Alright, then. *restarts Demigod*
And while I do agree with the notion that having a Team Pantheon option similar to Team Automatch in Company of Heroes is a good idea, its absense does not justify premades trying to have their way with the Pantheon as it is.