Good God, what is Hasbro doing? More spoilers! Skip this entire post if you don't want any S3 spoilers. Actually, if you haven't seen all of the episodes and don't want anything spoiled, skip this post. Better safe than sorry.
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Still here? Good. Here's yet another song. I'm just posting a link so that people scrolling by won't accidentally see anything (the thumbnail is a tad bit misleading; I nearly had a heart attack when I first saw it...). Listen/watch first, then read on. Spoilers to follow. (Also, here's a better version of the first song)
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While I did enjoy the other song, I'm not so sure I like this one as much. Soleron said the other one was just sort of explaining what was going on... and that's true. But I got a few laughs from it, and Spike is a better singer than I expected; I think that they captured how a good singing Spike should sing. I wouldn't mind at all if he sang more in the future. Also, the animation is a large part of why I was impressed. Seriously, Twilight's hair blowing in the wind was awesome! That really has nothing to do with the song, but... still.
This song though... It's not terrible or anything. The music is sorta catchy, and it's cute just like you'd expect, but it seems so.. random. And the lyrics are... less than stellar. Rainbow Dash with a mohawk was funny though, and I think she's my second favourite pony to hear sing (after Fluttershy... which is why I love the Find a Pet song so much). I dunno, maybe it'll fit in better with the whole episode. It could grow on me too; I didn't like the Flim Flam Brothers song at first, but I love it now.
Still, it confirms Cadance will return (which I am not upset about at all; I was very pleased with how her character turned out in the S2 finale). It shows off a new location that's pretty cool, and introduces some new species(?) called the Crystal Ponies... Or they're just from this city of crystals. Anyway, these were apparently rumored back in May, via new toys. Link.
Is Cadance part of some other kingdom that isn't part of Equestria? That seems odd; she spent a ton of time in Canterlot, or she wouldn't have babysat Twi. But maybe she was supposed to be there in the hopes that she would marry someone important to strengthen ties between two different kingdoms. Or it's just a city that we haven't seen before, and she's in charge of that.
I looked up the discussion on reddit, and some people mentioned being concerned that this is just a way to promote new toys. And it is... but so was the season 2 finale, and... well, I can't say that I don't think they can do a good job after that.
I'm terrible at avoiding spoilers.