I was at the Vancouver show that appeared on the Chaos in Motion DVD in 2008, he was fucking incredible that night and I have the bootleg from that show to back up that claim. I'm listening to Voices from that show right now and he's KILLING it. They even did the "thought disorder" verse and he again, killed it.
I agree with what a lot of people are saying...the human voice is inconsistent. And I know from experience, sometimes you can do ANYTHING...sometimes you're scraping by.
I did a gig a few weeks back where the first half of the gig, the voice was sounding and feeling awesome...about the middle of the gig I couldn't do ANYTHING I was trying. It was hell. But near the end it got back on track. My point is, his position is always going to be the most scrutinized because it's probably the most upfront. But he's one of my all time favourite singers and is going strong since 1991. He's inspiring!