yes you get rank and xp from AI's so finish your games
This is not always the case. Two scenarios that I have experienced:
1) Two humans on opposing team leave the game within the first 5 minutes. Me and my teammate decide to finish it out for the exp. and favor. We do so in another 10 minutes or so, but the game was never recorded at all.
2) Immediate disconnect upon game starting. I finished out the game against the AIs for the exp. and favor, but when I checked online a bit later, the win had been recorded as a loss with far less favor points. I think in this case, the game with the most humans in it (i.e. if I were the only one to disconnect and the other 3 humans played with 1 AI) becomes the game that is recorded for all who could have/should have participated.
I'm not sure if this is intended behaivor, or just the pantheon system being messed up. Probably the later.