These days a relatively high percentage of airports do not do annoucements. In general, I think tha this is a GoodIdea, in general, as they were generall inaudible, rarely useful and stopped you from sleeping. However, for the visually impared, I suspect, "please read the depature boards" is less helpful than it might be.
Many airports have induction loops for those with hearing difficulties, though. So, my question is, would it be possible for blind passengers to use these? The technology is already there, they could get information broadcast straight to them, and it wouldn't annoy other people. Of course, this would mean that they would have to put up with the annoucements that are so annoying for the rest of us. I guess, personalised voice messages to mobiles is too complicated.