Have you ever rewatched the first Season ? Namely Winter Wrap up ?
Every Character had a role in that Episode and a Reason to do what they do and Twilight had to fit in, definately one of the best Episodes .
Now Season 3 was "The Twilight Show" and the others were just...there, especially Pinkie was very raw in S3, now we have a Movie where Twilight goes on an Adventure without her Friends (Twilight Show) and in a less interesting setting .
Indeed, two steps backwards