One possible aspect to analyze in this fanfiction could be the character of the 'unwilling angel'. It might explore the internal conflict within the angel, perhaps being forced into a role it doesn't want in the Evangelion universe. This could add a new layer of complexity to the existing lore.
The unique feature could be the perspective. By focusing on an 'unwilling angel', it gives a fresh take on the Evangelion story. Instead of the usual focus on the pilots, we get to see the events from an angel's point of view, which might change how we perceive the battles and the overall narrative.
She might be a character representing the general state of women in a particular society or situation. Maybe she's a symbol for all those who are oppressed and are finally finding their voice to scream out in protest.
In general, the Evangelion mangas are considered good. They expand on the anime's universe, providing more depth and character development. However, it depends on personal preferences as some might find the style or pacing not to their liking.