Many years ago (about 2000s) I've emailed Naughty Dog (the company who created Crash Bandicoot) and suggest them to make a game with 2 sides of role play. We can choose whether to play as good guy or bad guy. But they didn't reply for my email so I guess they turned down my suggestion. But I think it's a cool idea. For examples if we play Mario Bross, we can play as Bowser (the dragoon) to destroy the kingdom.
The really problem here I think is that the moral of the game. I mean everybody (our teacher, our parent) always say bad guy always loose. So if the game made the bad guy win then may be the gamer (esp the kids) will think that it's cool enough to go bad.