Including both options seems like a good thing in theory but I think for TRUE motion control and not just lame ass wiggle waggle it needs to be so integrated and so precise that you CAN'T offer another option. Like it just won't easily transfer. The Wii games that provide both options have really LOUSY motion control where they're just mapping button pushes to gestures. That's why they can provide both because you just make it so instead of "waggle left" you push A.
There were N64 games that used the d-pad and provided both options. And in cases were both options were there I would use the d-pad since usually in those situations digital controls were more precise.
But I didn't want a d-pad when playing Super Mario 64, Zelda, F-Zero X, Goldeneye or Banjo-Kazooie. These were flagship titles and they just used the analog stick so perfectly you didn't want a d-pad for them. They wouldn't even work because it wasn't just like you just add a run button to digital controls. Remove the analog stick and you get shitty controls like in Super Mario 64 DS.
Providing the option is saying "in this game motion control is a gimmick". Now if they can provide the option I want it, better than forcing me to fight with motion controls. But it shouldn't be like that. When I play Wii Sports I never think "boy I wish I could just use a button to do this" because it doesn't make sense. The game and the controls are so tightly connected you can't imagine it working any other way.
The previous Wave Race games didn't just use the analog stick to replace a "fast" button on the d-pad controller. They needed it. Wave Race for the Wii should need motion control in the same way.