Personally I think the volume is just fine. you really don't wanna hear it when the double bass drum too high (live example: Primal Fear at GMM 2005).
Listen to the title trach of the album, nice and loud and tell me your heartbeat doesn't follow the kicks in the beginning.
One thing I always liked a bot AA is that everything fits and is very professionally mixed. WOOOS is no different. There is no star instrument in the band, they are all equally good and all get their strengths blended into the mix