I don't know why but the 1st story was fascinating to me. How the vikings are Earth pony legends is pretty symbolism by itself and how they can act tough over logic. I don't really tend to say that ending was a cop out or lazy writing, I think it was some sort of magic that was hidden there on the ground that happened to be released and transfer itself to Rockhoof. Probably just me though since I really like those kinds of details.
Of course, the 2nd story is more interesting than the other two. Probably because of how it was all Asian like and what it represents the Unicorns themselves. Intelligent and empathy. Ms. Mane is complex by her own tale, though I can't tell if the flowing mane means she has all powerful magic or not (A creator of Alicorn perhaps?). Not to mention, THAT ORANGE PONY!
So Torch-like dragon is in this legend. Either they're lazy at making dragons or that's Torch himself. Flash Magus (can't they come up a better name? Something other than Flash?) is RD that is similar to Dash but made the cockiness to the max, but they mix it pretty well i say.
Also, Scootaloo has been adopted by RD's parents off screen lol. No seriously, I have never seen these two saying this 'sister bond' so casually, not to mention act like one two. The hints are too strong for this episode.
Overall, nice world building episode. Not the best way of telling it but it works nonetheless.