It was a good episode overall and I do agree, it pushed ahead some good character building. Despite that, I just felt it lacked some depth to it though. It was better then some stuff we've seen in the past, but I have a hard time giving it a score of 8. I will give it an 8, as I've given somethings a 7 that truly deserved it, but next season I may have to re-evaulate my ranking system.
Some big moments I liked were Rainbow Dash coming to terms why she didn't want Scootaloo to truly go away to Lightning Dust. I think it started out as jealousy (of course) but when it got to the point that Scoot's was going to possibly hurt herself, it became genuine concern. That realization may have came too late, which is also a bit of a dig....
The new characters were nice to see, but Short Temper... or whatever his name was, was too much of a character and that only.
Lightning Dust was good to see again!
The Mane 6, while minimal in this episode, fit in well and weren't forced.
Parts I didn't like were Spitfire's sergeant style rant to Scootaloo. Don't get me wrong, it could have been a good scene and it was, but I felt the voice acting was all wrong as well as the lines delivered seemed to repeat and loop. It was clumsy and the voice actor failed to portray the yelling well. It seemed like they were struggling. I give them a D on that.
As mentioned above, Dash's realization may have come too late, meaning her main intentions were jealousy, which then shifted to true concern only when it was absolutely needed a the last minute.
So again, I give this episode an 8 overall.