Haha...Somehow I could tell by the nickname...But hey, it's music he can listen and like whatever bands he pleases...
By the way, Opeth are not riffbased? Of course they are, but their riffs are more emotional than anything pretty much alot of people can ever come up with. The slow parts are the beauty of Opeth. Without the slow parts, it won't be Opeth. Opeth is ALL about the transitions and the feel. Hope you understand.