I think all controllers have their strenghts and weaknesses, driving games may be better played with a force feedback steering wheel, a strategy game may be better played with keyboard and mouse, arcade classics may be better played with an arcade stick and so on.
I think the Wii-mote form factor has both its strenghts as well as its weaknesses, like an ordinary remote having both hands on the controller feels clumsy to me, for this the Sixaxis feels more natural to me, it's easier to combine complex button combinations together with its motion sensing ability or holding the device with both hands.