Small like a Hetzer, or big like a SU-100, the turretless TD's would have advantages, and disadvanteges, that would make for funny gameplay. They would have a small, low silohuette (except for perhaps the Jagdtiger) which would make them hard targets, at a distance. The lack of a turret, however, would make them difficult to use in built-up areas' like TT city, or in a densely wooded area. Actually as far as gameplay, they would not be so uber as would first be suspected. As for the Turreted American TD's, they would have the advantage of a turret, but they would have thin armor, so they would have to rely on being quick on the draw, so to speak. TD's would contribute greatly to gameplay, IMHO.