Where to begin? First, I want to get this off my chest: They redeemed Flash Sentry! To me, at least, I think they did a good job of making him a better character. There was actually a personality for us to latch onto, and it made it so much better. (Though I did laugh when he was being mean to Twilight, I even nicknamed him ******bag Sentry, forgive me!)
Apart from that, the animation has greatly improved. Most notably, the way the characters move, especially the Dazzlings, and the epic battle at the end. I also love the pacing, the fact that, unlike the first EG movie, there were no needless subplots that didn't go anywhere. It was straight to the point: Stop the villains, be careful about it, and deliver an epic song while doing so.
The villains themselves were...actually pretty awesome. Sonata Dusk was adorable, as we all know, but Adagio was less of an 'alpha b****' and more of an actual threat. I really enjoyed the fact that she just rolled with Sonata's antics instead of being rough like Aria Blaze, and Kazumi Evans did a great job of voicing her.
Now, the songs...How to describe them exactly? Nothing short of brilliant. While there are a few that are the usual for MLP (E.G Shake Your Tail, Awesome as I Wanna be) there were a few that stood out, namely Welcome to the Show. Holy Hall, it blew out my expectations. After listening to the soundtrack and enjoying it, then watching it in context...I have to say, the terrifying beat coupled with the amazing visuals did not disappoint. Also the credits song, Shine Like Rainbows. I don't know why, exactly, but it reminded me of Celestia's Ballad, I guess because it sounded really sweet. (And then the choir came in at the end.../)^3^(\)
Now, the part of the movie everyone may or may not overlook: Sunset Shimmer.
Her road to redemption was a hard one, and while I was prepared to give her a second chance, I can honestly say that it was worth it. I mean, you could tell she really wanted to be accepted, and honestly I did feel bad when people were glaring at her, even if she did deserve it. There was actually some good, believable character development, and I have to say it was nice seeing that it all worked out for her in the end.
Finally, the ultimate MLP base breaker...Flash Sentry. I know I already ,entitled him, but I want to get my point across, so here we go. I actually warmed up to Flash Sentry during Rainbow Rocks. The fact that he actually had some kind of personality this time around, he's awkward and kind of dorky. For some reason, however, I found the perfect case of irony, possibly in any MLP media.
I loved that Flash Sentry didn't have a lot of screen time.
I understand that those who disliked him did so because he was a boring character, and he didn't contribute much to the plot, but this time that actually worked in his favour.
By not giving him much screen time, they made room for Sunset Shimmers own development, and it also didn't feel like he was being forced at us as a 'nice guy who likes Twilight'. Because of this, I warmed up to him and I hope that if there's a third EG movie, he'll have the character development. I can't say I love him exactly, but I am ready to give him a third chance.
Overall, the film was a big improvement over the first, with better pacing, more effective villains, the Bass Cannon, better character development, a more epic climax, and more rounded out songs and storyline. Oh, and also a Rainbow Crystal Sky Alicorn Princess in the climax, don't forget about that.