So I was trying this week's campaign challenges (which were a complete pain in the arse), and was contemplating trying a Mythic run. From what I read, the only reward besides bragging rights, was some medal on Waypoint. Is it really worth the time, and patience to do this? Watching a couple of videos, it looks like the only way to take down Elites is melee from behind, which of course I'm not the greatest at.
I beat LASO with a friend of mine, and it was still tough. Although, you can still do it if you keep trying. Playing Coop makes it easier, though, since checkpoints exist on coop. Assassinating elites is troublesome, but if you throw a grenade in front of them they'll stop and duck, which leaves them wide open. Also, on the bright side, Knights are super easy to kill on LASO. You get the LASO Emblem too, by the way. I just wish you more than that, though.
Also, you can always use the save and quit method to avoid getting sent back to the start of the level when you die. Of course I think that would remove the Mythic part of what you're trying to do according to some people.
By the edge of those wilds, warriors have charged. But now the years have passed, the generals have left and the grass grows in the armors hollow on the hill.