Dragons are Vikings
I'm jut going to say it, after seeing the Gauntlet of Fire it proved my theory of four years ago. The Dragon culture is inspired by that of the Huns, The Mongolian Hordes and for the most part, the Vikings, hell even there armor seems viking inspired.
Pony Culture was based on Ancient Greeks(Lauren Faust said once)
According to Big Jim, this is not the last we have seen of the Dragons, in fact there will be a couple more episodes(Ones with Spike) and more on the Dragons even..yes this was confirmed at the last panel..a Hearths Warming Dragons episode.
What would be interesting is if some dragons...fear change, fear the idea of being Equestrianized(Become pony like, or adopt Pony customs)and fight against it. Dragon Lord Ember may try to officially end the pillaging and create new relationships with Dragons.