Fridge Brilliance: In the fairy tale, Cinderella's salvation comes from dancing at a ball, so it makes perfect sense to have Mary be a dancer.
Likewise, the climax at the dance competition.
The Scrappy: Holy carp, Dominique. She is an Abusive Parent and a complete Jerk Ass, and she has absolutely no redeeming qualities whatsoever. It's a wonder how she managed to get away with her treatment of Mary before the events of the film.
Surprisingly Improved Sequel: It did much better with critics than A Cinderella Story, and ranked as January 2009's No. 1 TV film when it aired on ABC Family. It also won the 2010 Writers Guild of America Award for Children's script-long form or special, which says a lot considering the first film was nominated for a Razzie.
The fact that there is another sequel (that will also have a musical theme, and star Lucy Hale, who is known for looking like Selena) in the works supports this.
The Woobie: Admit it, you wanted to hug Mary at least once during this movie. The poor girl just can't catch a break. Seriously, the way her so called family treats her crosses into abusive territory.