Those who know the MLP fanbase most likely know that Merriwether Williams is a VERY controversial figure, mainly due to "Mysterious Mare Do Well". I myself had some (very) strong issues with that episode, but after watching this episode, I can say with complete certainty that she has redeemed herself in my eyes.
First, characterization. One of the main criticisms about Williams is that she flanderized Rainbow Dash from a Jerk With A Heart Of Gold
who cared about her friends and family to a straight up Jerk Ass
who cared only for glory and fame. In WA though, Dash's portrayal is spot on. Yes, she's confidant and brash, but its the LOVABLE kind of confidance she's known for, and she proves exactly WHY she's the Bearer of Loyalty by the end.
Secondly, Spitfire. Now, I know a lot of people were turned off by Spitfire's actions, but to me, it had the exact opposite effect. Spitfire is the instructor
of the Academy. Its her job
to act as a drill sergeant, and the fact that she didn't give Dash special treatment proves that she's a good instructor. It doesn't mater who applies to the Academy, an instructor can't afford to play favorites. If anything, this episode made me like Spitfire even more
, as it showed that, despite her normally casual and laid-back attitude, she knows how to take her job seriously when she needs to. The perfect Wonderbolt role model.
Finally, Lightning Dust. My main reason for including her is because...she's surprisingly mature, as an antagonist. She actually comes very close to being a sociopath in a kid's show, and she serves as an example of what Dash could become if she lets her pride go to her head, which I felt was a good contrast between them.
In closing, this episode showed Dash at her best, increased my admiration for a fan favorite side character, and had a surprisingly mature antagonist. This is possibly the best episode of Season 3, and Merriwether has fully redeemed herself in my eyes. 10/10, would watch again...and again...and again.