Plenty of thrash songs, on the other hand, will throw in 30 riffs in a 5 minute song along with plenty of tempo changes, which accomplishes more than Opeth does in an entire album. Hell, Burning of Sodom does it in a mere 3 minutes. Power metal has plenty of great leads don't slack off in the riff department either, and even flower bands like Rhapsody certainly demonstrate far more diversity than Opeth.