Comment by wyldfire

The player AI driving the game would score a permanent based on things like power, toughness, cmc with varying weights. And it would use that score to decide which permanent to play when it could cast more than one. A pretty simple model but probably an effective starting point.

Actually, it was a bit more abstract: it scored a game state where it considered this players permanents, the opponents permanents, this players life total, opponents life total(s).