Mikael's growls sounded incredible in Opeth and Katatonia, but his work on Bloodbath was never really impressive to me. He's a great growler in Opeth's style, but compared to beasts like Tägtgren, Mullen or Pillard, he falls quite short. Definitely not fit for a full death metal outfit IMO.
I mean, after seeing both Opeth and MDB live, I can safely say that Aaron Stainthorpe has a far more powerful growl and he is never discussed among death metal vocalists.
Mike's growl went to the toilet after rejoining Bloodbath. He wasn't used to do 100% growls live, he started to smoke more and got drunk in plenty. Bloodbath over Bloodstock is embarassing to watch. Lamentations, in the other side, is incredible.