Sunn O))): "the most influential metal group of the decade"? Nah, that would be Black Sabbath - as it would be for any decade.
Facetious pedantry aside, in this article for the Guardian John Doran does genuinely make a good case for what might initially seem a rather bold and contentious claim. "Like the giant celestial body they share a name with homophonically", he writes, "they exert a massive amount of gravity on the culture that surrounds them, drawing more into their orbit while radiating giant waves of creative energy back outwards." What is striking is that that impact extends far beyond what might be conventionally considered as the outer limits of metal - Doran refers to SWSL favourites Blanck Mass and Marissa Nadler as well as The Bug and Anna von Hausswolff as artists whose work carries Sunn O)))'s imprint, even if only subconsciously, and also cites the soundtrack compositions of Nick Cave, Warren Ellis and Geoff Barrow.
Doran's argument is that since the band emerged in the late 90s it's culture that has changed, partially through their influence. While I don't really buy the claim that "metal has, for the most part, always been modernist and avant garde" (as Doran himself admits, throughout its history it's been associated with regressive and reactionary attitudes), it's certainly true that it is now recognised as "a valid art form" in the right hands - no longer the laughable, childish preserve of nerds.
Seeking to identify the secret of Sunn O)))'s appeal, though, Doran is less convincing, suggesting that listening to them is a transcendental experience not dissimilar to that enjoyed through yoga or meditation. And I wish there was some acknowledgement among Sunn O))) acolytes that the monks' habits, the copious quantities of dry ice and the raised claw-hands threaten to push the live shows from drama into pantomime. Metal has always had an element of excess and ridiculousness about it - and Sunn O))) are no different, even if po-faced beardstrokers refuse to recognise it.