I really liked the movie until her trip back to Ireland.
After that, she suddenly lost all of being the protagonist for me, and I think it was incredibly rushed and badly developed in that part.
Jim Farrell had 0 character development, and the whole section was a crammed-in 30 minutes of bad things happening both from other characters and Eilis. Her mother, Nancy, that one boss, and other people essentially doing what they could to say "Stay here in Ireland."
And Eilis went from seeming to be against all of that to suddenly being okay with it all and ignoring Tony. She literally would've sensibly said "I'm in love!" to Nancy or her mother instead of just weakly saying "I'm returning to America."
Her stand-up to Miss Kelly was even worse and I wasn't rooting for her, because it wasn't like it was a realization of what was happening. She very well knew that she was essentially sitting Tony and her happiness in America aside, with scenes like the letters in the drawer, or each time she would weakly argue and then accept someone's suggestion.
The scene felt like she was just all of a sudden upset that someone else found out what she had left behind. She did not "win" against Miss Kelly. She just decided "Well, guess I have to reveal everything if I don't want the old boss of mine to do so!" By the time this scene occurred, she essentially seemed all ready to stay in Ireland with Jim, her new job, and everything.
It wasn't fitting for her at all from what we'd seen of her personality the rest of the movie. I understand that she would've had a reaction to returning home, and part of it would've been feelings to stay there, but the random mini-relationship with Jim as well as just accepting what everyone else basically told her to do was not fitting with who she was.
Her sister Rose's meaning to her was basically thrown out of the movie at that point as well. Her sister, who did her best to help her out and believed in Eilis' new life in America. Rose is not mentioned for the rest of the movie and Eilis basically forgets how much her sister pushed for that as well.
Basically lost all of my sympathy or liking of her, leaving the rest of the movie as being pretty flat. I didn't need or even want some idealistic romance movie. Clearly it was about where "home" is - but the way they did the conflict was horrible.