We've all been there.  An ally leaves, and the AI takes over.  The AI is stupid almost to the point of being funny, and simply feeds the opponent in most cases.  For matches between inexperienced players, it will be acceptable for leavers to be replaced by Hard or Nightmare AI.  In games with players who are even moderately experienced however, it will be even more a handicap than having no ally at all.

In light of that, I believe there ought to be a setting in the game options for what happens when a player leaves.  Either the AI takes over for them, or their Demigod simply dies and doesn't return, and their gold is distributed to the rest of the team (their items converted into gold or something like that I guess).  I think this is a somewhat simple and good solution to the problem.

I would also love to see some option for allowing players to actually take over their ally's Demigod after the ally has left the game.  I'm not sure if this is possible with the way the game is coded / the way the UI is setup, though.  It would be nice for a player with great multitasking skills to at least have the prospect of controlling two (or even three, though God help them) Demigods at once to try and overcome the opposing team. 

I like the idea of these all simply being options and not necessities so that players can adjust the setting according to their preferences and abilities.  In any case, leavers / disconnects are going to be a fact of life with this game, so it would be nice if we were not necessarily forced into the worst scenario when that happens (though it's always going to be bad).  At the moment, the AI is more a liability for decent players than anything else.