@humanity: Soooo you watched a couple of transformations sequences and judged the show based solely on that and a rough understanding of the plot? Man, that is profoundly cynical. Even as unabashedly fan-servicey and goofy as the show is I feel that is a little disrespectful to the creators.
It may have a wonderful plot - there are people working on it who were in part responsible for Gurren Lagann and that was a great show. But teenage girls transforming into what can be described as "outfits" in the loosest possible meaning of the word, complete with G-string panties and bouncy unmentionables is-what-it-is man.
It's pretty dumb, but they lampshade it many many times over the course of the show. Characters think the main character's an exhibitionist while she absolutely hates wearing the thing. I'll clarify though that the youtube video you posted was the antagonist transforming, a woman who is in at least her twenties.
It's not just a "Here we'll parade the characters around in thongs and bare midriffs and then act like that's normal" thing. It actually has some cool ramifications on the arc of the plot, and they mention it all the time. But whatever, the show is still only a kind-of-good action-comedy with some amazing visuals. Criticising an outfit (rarely) worn by only two characters just seems like a pretty shallow way of judging the series.