Size Recognition: Will Natal work with small children? Will a 3 year old be able to bat at balls with Natal like they can swing a tennis racket in Wii Sports?
Finite Movement: Natal can see you swing your arms and legs and even turn your arms enough to turn a steering wheel, but it can't see your hands turn in minute angles or determine your wrist position at all. What does this mean? Well it immediately eliminates options of sword fighting and advanced finite sports like those found in Wii Sports Resort (Bowling, Tennis, Archery, etc.), which require precise positioning of the hands and wrists.
Basic and Uncorrectable Control Limitations: No controller means it's not realistically useful for something like a shooter. You can't point and shoot and be accurate without some form of IR. You can't move without walking in place or stepping forward and backward which is not only uncomfortable, but signifficantly slower than playing with a joystick. Any genre that requires a lot of inputs (shooting, fighting, action, adventure, action RPGs, most sports games, platformers, and pretty much anything that requires movement on any part from the player in any forward or backwards direction) will be limited to very minor and most likely inconvenient usees of the motion controls. A limit not present in controller based motions.
