I think I saw him around 2007 or 2008 and I couldn't understand half of what was growled on stage and most of the "hits" were unrecognizable. He may have changed a bit in stage presence since then, but the voice is long gone.
Yeah @folsom_lives, that's what I'm most worried about. Since a lot of what makes Dylan Dylan for me is his lyricism and storytelling, so if that's gone I'm a little leery.