What seems to happen is that in metal, people attribute the inclusion of any atypical elements (even simply within a particular genre) as "progressive", even though these elements have existed both in metal and in other music for years and years. Opeth's use of acoustic and clean electric guitar interludes comes to mind.
What really matters to me, more than being ahead of or behind or with it's time, is whether the music is FUCKING GOOD.
While I'm here though, GOAT HORN gets my vote for best band that's 20+ years behind it's time. These guys are only a year or two older than me and they play some kick-ass traditional metal with some thrashy tendencies!