When I got into Opeth, one of the things that I found most fascinating was that they were a 'death metal band' that could hit you with beautiful, calm and clean sections once in a while. At that time, I didn't really like death metal vocals at all, but it was the huge contrast that made both sides (heavy/brutal and clean/beautiful) interesting to me. Then, by listening to them often, I learned that the heavy sections (including growls) could be incredibly beautiful as well.
So ofcourse new Opeth isn't going to have such a profound effect on me anymore. But that's okay, I think they still kick ass and I really respect Mikael not liking DM vocals that much anymore. I hope he doesn't have to do them anymore in the future, if he really doesn't like them anymore. That Rock Am Ring concert sounded pretty good, by the way, even the growls. I didn't think it was that much weaker than on the Royal Albert Hall DVD.
Guess I'm going to see them live soon, before they decide to drop the death metal altogether. I have to hear 'Deliverance' and 'Blackwater Park' live, one more time. If they throw in 'Ghost of Perdition' or even 'The Moor' or whatever then I'll die happy.
At the end of the day, if they want to play cheesy 70's prog/Rainbow/Dio stuff, they should totally do it. They're quite good at it. But indeed, not as good as the original bands were.