that's crazy talk man, i have heard these stories, but it's not the case, it's hardly like bob dylan.... lets be fair he's knocking on 50 now, he's not gonna be what he was, but i bet they still get best live show in every award going this time next year. As for the album well i know they get tweaked but his voice is faultless track three is a prime example and one of a hatful that was recorded in one take. He sounded ok on BBC and on Good Morning America too.
I don't buy into all this talk about his voice, he's just getting older and like everything stuff deteriorates a little
i also can't picture any U2 fan booing - they are like the best live act going and i'm a big Bruce Springsteen fan