The ability to play as a kid survivor would be great. The kid survivor would have pros and cons. The pros being the kid can run faster, getting away from zombies/bandits easier. The cons would be carrying less stuff, the ability to only use a pistol and when the kid is scared it screams drawing more attention to it. I think this would make for an awesome and very challenging aspect to the game (granted it is already very challenging). But if you add kids then we cannot forget about kid zombies. Because let's face it kid zombies are far creepier than adult zombies.