My thoughts so far:
1. I agree with the fact that the music sounds like soulless pop. I hope the trailer doesn't complete reflect the final product, because I believe Daniel Ingram could do better than this. While I do think the battle of the bands idea sounds interesting, I hope that they put a twist on said cliche like they did with some of the high school and teen sitcom cliches.
2. I notice that Vinyl Scratch has been featured quite a bit in the material concerning Rainbow Rocks, being on the cover of the book, and it might be just me but a slight, but significant amount of focus seemed to be on her. I'm worried about her ascending background pony status because it might be seen as-dare I say it- pandering.
3. I'm also worried about the lack of Sunset Shimmer in the trailer. It would be disappointing if Sunset didn't appear or was show or mentioned very little because how could any of the characters just ignore for her previous actions. Plus, I think she has some potential to be an interesting reformed-villain type character. (While I'm on the topic of characterization, how's about the writer give Flash Sentry a an actual personality.)
To sum up, I'm excited to see the sequel because I really wanted the human universe to be expanded a little more, but a little voice in my head is nagging me to be cautious and not to get my hopes up too high. Either way I'm definitely watching this. Wait, when did they say Rainbow Rocks would be released?
Trailer: Fall 2014
....NOOOOOOOOOOOO-etc.