It's supposed to be a more alternative/industrial-sounding band. Apparently, Thomen doesn't want to play good music anymore. Anywho, though he's good at what he does, I can't say it would be that hard to find a replacement drummer. You could throw a dart in the air in the middle of Germany, and I guarantee that it would land on a double-bass drummer nine times out of ten. It does suck, however, that Blind Guardian will no longer be keeping their original lineup. They seemed to be the only metal band in existence to not have a revolving door of musicians.
Stay metal. Never rust.
Met-Al