Kindly critique, is is quick and dirty so I understand it may not be clear, it is merely a conceptual framework.
By straightmaned I mean any time she goes into a depressive state, which she did in almost all of those.
Sadly I must disagree. One cannot just have interesting situations arise without a varied spectrum of responses. Without that the character does not have complex emotions or motivations. Which are required for depth.
A demonstration. Using Rarity, the character with the most depth and some antiquated psychology as a convenient way of ordering her personality.
Becoming Popular is representative of Rarity’s id. Her primary motivation, joy and fear. She wants to be acknowledged, wanted and admired but also fears being cast aside as a Jane Doe.
This is present throughout the episode, encapsulated by this song and expanded upon by the Nightmare Rarity comic.
Beyond this, the song also shows us another important thing with Rarity. Simply that she is beating the Elites at their own social game.
She shows up and through her charm and tact catches the interest of Fancy Pants at the Derby. Later she becomes a must have guest at parties, even to the extent that the Elites are desperate to have her. And during the song she becomes the toast of High Society.
The fact that she can do this ties into her reinventing herself at a young age (Cutie Mark Chronicles). Her success at doing this and actually outclassing the real Elites makes Rarity into something Jefferson called “Natural Aristocracy” in this area.
Essentially, she made herself and sits of the top of this esoteric hierarchy .
This is also part of a theme in the episode in question: being genuine. Not being genuine led Rarity astray in this episode, obviously, however she was still more genuine than the Elites. She genuinely enjoyed the events whereas they came across as cynically bemused by them (the derby is a good example of this) but most importantly she was not afraid to stand out. In Becoming Popular she uses her clout to cause the Elites to look favorably upon things they are initially cold towards or unsure of.
Now Generosity. Reflective of Rarity’s Superego which governs what could be considered one’s moral functions. In Rarity’s case her generosity.
This song does more for her generosity than simply singing about it. It also shows that Rarity holds the charitable idea that the people she helps will do something to return the kindness at some point in their own way.
This shows that she values and believes in the generosity of others rather than simply being generous.
Particularly when one considers that the openended nature of this belief means Rarity does not particularly care when or how the kindness is repaid, the idea of it is more important.
Also, during this episode, Rarity does have her kindness repaid and uses the opportunity to be more generous (at the beginning by giving the tickets to her friends and tipping the Bellhop over and over).
Lastly there is Art of the Dress. This is her Ego, the part which reconciles the id and superego in a productive manner.
How is obvious: she is trying to balance her own artistic decisions with catering to her friends.
Beyond this the song shows little beyond being a show of her generosity and artistic skill.
But it does show something. She has her dresses reflect the personality of her friends. This displays that her style has substance behind it, like any good artist. It also shows that she is not a superficial person, she looks beyond the surface.
That is her depth from 3 songs.