As always I'm a bit late (waiting Italian subtitles) but now I've seen this episode.
Besides the plot itself I liked the few background informations we got about dragons, changelings and the map too.
Those are gold for a game master like me.
First: never invite a dragon to the Crystal Empire or it will eat all the buildings
Second: a major stake in the internal policy of changelings, just to introduce the future episode about Thorax's brother.
Third: the Map is still evolving its ability beyond Mane6, but apparently for Spike it marks only incoming friendship problems, not something to solve. Maybe it's because he doesn't have a cutie mark?