Good god why does it matter? Putting aside the fact that not every game will benefit from motion control. Neither implementations are the most optimal or accurate possible. And really why does it need to be yet? Many Wii games are simple enough that they don't even need half the power of the wiimote. While there are other games which suffer from the current wiimote even with motion+ there will still be games which require even better accuracy and need spacial readings on top of motion.
Even if we agreed the sixaxis has the same relational potential as the wiimote they both suffer from not being able to get true spacial readings.