Samba De Amigo is an excellent example of the kind of positional feedback here. Go ahead and do that with headphones.
Another example is No More Heroes. Right before the boss battles, Sylvia calls Travis’ cell phone. The volume was at low enough level coming out of the Wii remote (and only the Wii remote) that it encouraged me as the player to hold it to my ear like an actual cell phone. This added a new layer of interactivity that I enjoyed. Headphones would have removed that experience while a good surround sound would have contributed to it.
No one is saying that a Wii remote speaker is better than surround sound by itself. The Wii remote speaker adds an extra layer to make it better. Headphones remove that extra layer even if they give a better surround sound experience.
Maybe if he taped them to his controller 