I think Switch will neither really satisfy the sky-high Nintendo enthusiasts, but nor will it satisfy the "Nintendo is doomed" crowd, lol.
That's because I think it will perform right in the middle.
It won't stop Nintendo's declining hardware numbers nor will be it be a credible "home console" (it will be mainly 3DS owners buying it).
But it won't "flop" either. It's a Nintendo portable, there's still a good 12-15 million people in each of the three major territories willing to buy one I think unless Nintendo make multiple stupid decisions.