Also, are mirror matches really a problem? If a game is underlyingly good (e.g. Chess), then mirror matches don't diminish the game, and if a game is underlyingly bad (e.g. Tic-Tac-Toe), then mirror matches are the least of the problems.
Even your basic Smithy-Big-Money mirror can have different outcomes based on more than shuffle luck--i.e. how early do you go with Province over Gold if you have $8? How soon do you get Duchies when you have $6? When do you get Estate over Silver? Sure, such a game is usually not as interesting as one in which you have to choose between, say, Silk Road and Bishop strategies, but then again, games where you only buy Smithy, basic Treasures, and basic VP aren't all that common.