Personally. Epic is individual. Epic (long short, technical/easy, stunning ugly) are all personal to me. I have had truly epic rides of 5 hours or the most technical single track *I* can ride...I went back 3 years later and the ride could no longer be epic. It didn't offer any challenge, cardio or technical. At the time, I almost fell unconsious, puked and bonked harder than in any other sport (the day I fell in love haha) I have also done 1 hour very technical and brutal rides or pure unadulteraded downhill that were epic. I could probably take a couple of people from here and they would enjoy it...it would be fun and challenging, but not epic...
If Randolph were 100% right than the only people who could truly define epic, would be the best. The elite. In that case no ride, no matter how hard or how brutal, would ever be epic as someone else would always be going longer and harder. How can a 'brutal' measly 8 hour ride (pathetic

) compare to the 6 days of the trans rocky (8 to 12 hours a day on single track or non existant trails)? Or the 7 days of the trans alp? Or a 24 hour race ridden solo (of a real trail)? Or the Downhill race in Golden which lasts, at full speed, almost 30minutes. Nothing would ever be epic, except for those elite riders that can loft the bar high enough.
regardless of the purety of its definition...epic is personal but still, meant to be used sparingly, for those moments that were truly achievements of the time.