Well, I don't think acknowledging that he might die or lose his motivation is "naysaying" or "doom and gloom." That might happen with any author, and is a good reason not to read ongoing series, especially very long ones that are written slowly. (There are fantasy fans who won't touch new epic series for this very reason.) And we all have instincts about what's likely that are irrational but hard to shake. As with anything, no one really knows what tomorrow will bring.
I don't think 2017 is out of the question for Winds
I think allowing an adaptation while the show was ongoing was a poor decision in a lot of ways. I understand, of course, that you have to pursue network interest when it exists, but the show has exacerbated delays in the books, and is probably going to have a rough time itself constructing an ending without source material.