Sounds like putting is a pain the arse, just like Wii Sports Golf, due to the oft-discussed problem with the Wii not being ideal at tracking the necessary, sublte translations inherent to putting. This begs the question, "If the game were designed so that you putted with the IR camera facing the sensor bar, (not with the camera facing down as you naturally would) would it allow for better, more responsive and realistic putting?"
I think the answer is yes. Maybe they could make a mirror periph that you could attach to the front of the controller that would enable the IR lights to be seen, while holding the controller down, thus allowing the Wii to know exactly what's going on in the Z direction. Sounds admittedly ridiculous, but I think it's a viable solution.