All very true but a blind passenger will not be able to see what is on the other side of that exit, be it fire, an incline, water or any other of the many possible hazards. They will also not be able to see how to get off of the wing, bearing in mind that not all o/w exits come equipped with slides.
Most blind have a photographic memory for routes, obstacles, etc.
Yes, but they do need to have travelled the route before. Unless someone regularly exits their house by jumping from an aircraft wing onto unknown ground/debris, that will not help in the slightest!
For those reasons, blind passengers are not permitted to sit beside an overwing exit and any crew allowing this are on a UK registered aircraft are contravening the CAA regulations.