Mickey Dee was amazing on those early King Diamond albums, he really set the tone for the band's sound going forward. With all the histrionics that go on up front, I sometimes forget how critical the drummer is to the overall sound of this band. His drumming came across as spontaneous, dynamic and nuanced... he's definitely missed.
From what I've seen of Matt Thompson, he looks like a beast of a drummer as well. He was killer when I saw them live. I don't know if it's the production or what, but on those later KD albums like GMYSP, his drum sound comes across as muted and subdued.