Metal, for all its anti-establishment credentials, can often be quite conservative. Many of the same old tropes have been rolled out again and again for the past four decades or so. Whilst that’s not a major problem for many metal fans, it is arguable that the same recycled ideas just don’t have the same impact that they once did. What once seemed impossibly heavy, deafeningly loud, even shocking or transgressive, can now be played on mainstream radio without anyone raising an eyebrow.