You know, everytime I hear this show and then listen to people critisize, it makes me realize it's all relative.
Are the keys dropped? Yes? Are the vocals on, pitch wise? Yes. Does he still sound like himself? Yes.
Does he still sound better than almost anyone out there? Yes.
I've already stated that I (and many others) prefer SP's voice Frontier's and beyond, and I know that thousands of singers would DIE to sound as good as SP in his "diminished state"
His voice is great in any of the 3 states that it's been in and is still one of the 2 or 3 most recognizable in the history of Rock/Popular music.
Anyone that argues that there is something wrong with this performance, other than a lyric slip-up, or the fact that the keys are dropped and they just don't like that, doesn't know anything about singing.