Ok now if any of you have played any racing games such as Excite truck (not sure about NFS carbon) but the controls is done where you hold the wii remote and have the face of it faced towards you.
now in the video of Prostreet you can see the player isn't holding it like all the racing games before it, he's holding it like you would hold the controller if you were playing Super Paper Mario. So my first guess is that this "KID" is not holding it right (technically its the same, but the wii remote can sense how its being held anyways), and I say kid because if you look at the players hands, it looks like a 11 year old playing this. Plus he appears to be playing the wii like every other newb to the Wii, ridiculous movement that's not needed.
I believe that you are wrong about how to hold the remote for Excite Truck. I found the controls were more responsive when the buttons were facing the ceiling. This was confirmed for me when doing jumps and tilting the controller. When it was totally level the truck was slightly pointed down, so maybe there's a slight angle compensation based on how a normal person would typically hold a controller (at a slight angle). I do not think at all that the button side of the controller should be perpendicular to the floor, which sounds like what you're suggesting.
I personally thought the controls were really great for ET once I got used to the small turning radius, which didn't take all that long really considering it was the first game I played on the Wii.