I would love a game with a subway diverter so you don't know from where the ball will launch when it comes out of one of several exits. Subways are fun but I think what I didn't find fun after a while is that you know where the ball will come from. Adding randomness would be awesome. Not sure if a game does this already?

I don't see how adding a diverter in the subway could automatically be categorized as "bad design" depending on theme and code implementation it could become an integral part of a game.