It is true that a rather unprecedented number of people expressed that they experienced enlightenment or at least a change of heart regarding 3D once they got their hands on the 3DS. Having said that, it is almost guaruanteed that not everyone will feel the same way about it. As such, for a lot of people, the 3DS will fail to fulfill their expectations and they will be disappointed.
Having said that, I still think the 3DS is going to be a massive success. But not beacuse of the 3D effect (although it might help, we don't know yet), but beacuse of the sheer versatility of the system. Don't like the 3D effect? That is ok, you can tone it down or completely turn it off using the slider. Don't like the control with the D-pad? That is fine, you can use the slider pad instead.
That, I think, is the system's greatest advantage, that there are so many ways one can enjoy using it. Regardless if you are core or casual or love 3D or not, it seems like there is always going to be something for you to enjoy. And if that turns out to be the case, I think the 3DS is going to resonate very well with the gaming audience at large.