Regarding the voice issue:
Since around Popmart, Bono's voice has generally been more inconsistent/fragile than previously. Over the recent tour, he has had very good days and some pretty bad ones. During most of the first leg he sounded quite good, although he was not in very good form around the end of the first leg - particularly at MSG his soaring high notes sounded forced, flat and raspy like in the new Stay recording. I thought this was evident during the few European leg performances I heard - Barcelona, Italy, etc. During the third leg, I would say that Bono sounded quite good, maybe even better than during the first leg. At the two 3rd leg MSG shows I attended he sounded terrific and really soared at moments, where he before had more limited range. He was also really on at a few other shows, too.
I don't know when the new version of Stay was recorded, but I would venture to stay it was either at the end of the first leg / during the second leg or around the Superbowl. I don't think Bono's voice is suffering from recent cumulative over use, it's other factors - talking too much, diet, weather, temporary respiratory problems - which he can suffer from at any given time (granted this is coming from someone inexpert in these areas).
His Superbowl performance, was, in my opinion, poor because of his unusual amount of talking at the World Economic Forum and the sound system/mix was quite unforgiving. I don't think this performance in any way portends that his voice will sound like this going forward.
Generally, I do believe that even on Bono's best nights his voice is not quite as strong as it was on average nights during previous tours. Even Bono himself readily has admitted to this, and in fact, his own personal assessment was maybe even less forgiving in which, to paraphrase a recent quote in Hot Press magazine, he really regrets smoking and drinking so much, as that it really has changed his voice and that he can't soar like he used to.
Still, I believe Bono's voice is quite impressive and a lot of the change in Bono's voice is the result of maturation and intended changes, not necessarily
degradation. His voice has a certain soul that it never did before and more character. His voice, as it has been since the recording of ATYCLB, has, on balance, received much more praise than criticism and in several places I have his voice described as one of the best in R&R history and admired by numerous artists.
While this issue is quite contentious for many, I think that most will agree that Bono?s voice is ever changing.
karl