There was something that (mildly) bugged me about Discord's character. For Applejack, Pinkie Pie, and Rarity, he formed a pattern of manipulating each pony to abandon the element of harmony that they represent. But in Rainbow Dash's case, he manipulated her into abandoning her loyalty for her friends... in favor of her loyalty to an entire pegasus pony city that might have also been her hometown. And as has already been noted, he never actually manipulated Fluttershy into abandoning her kindness; he just kinda arbitrarily blasted her full of his magic to make her mean. For both Rainbow Dash and Fluttershy, his previously established pattern was broken.
Aside from that, I loved the new episode. I can't wait for the second. It's going to feel weird, though, to have to wait an entire week between episodes, particularly after having seen season 1 in marathon-like bursts...