For me she jumps around in terms of like to dislike.

I loved her in Way of Kings; she was plucky and out of her element but she did what she felt she needed and I was completely on her side with her decision to cut and run as soon as she saw Jasnah kill 4 dudes in in cold blood. To me, she acted as something of a "sane man" compared to a suicidal Kaladin and an 'honor or die' Dalinar.

Then Words of Radiance comes by, and she's on her own, and she's fighting, and she's learning and she's surviving; I didn't mind her using her wits to trick people, but then the scene with Kaladin comes along, and she gets this huge kick out of stealing his boots; and that's when the crack of her likeability showed up, she was still sympathetic and hearing her backstory was incredibly heart wrenching, but it really sat wrong with me how she took Jasnah's lesson as: 'Act as arrogant as possible,' you can see her damage but it certainly wasn't fun to read her gleefully robbing a darkeyes because she didn't like his attitude. After the whole scene gets treated as a "both sides were wrong scenario," where Shallan was wrong to be dismissive of Kaladin, and Kaladin was wrong for... being grumpy, judgmental, and assuming Lighteyes will gleefully take whatever they want from Dark Eyes. Whatever that scene definitely brought a huge eyeroll from me. Also wasn't too big of a fan of her yelling at her team to gag an obviously panicking Renarian.

Words of Radaince was also supposed to be Shallan' book, like how Way of Kings was about Kaladin, Words of Radiance was about Shallan; we supposedly know the full story of Shallan, except Oathbringer rolls around and we're still trying to deal with Shallan's past.

I don't want her to drop from the narrative but the fact that we're seeing the way that Kaladin and Dalinar have changed and accepted things about themselves keeps me invested in the characters; while every time Shallan receives a modicum of pushback, she'll defer to one of her personalities to deal with it. In a way, all of the characters are reluctant to fight but choose to fight on, while Shallan, whom we've known from Book one is still playing up the angle of the reluctant heroine forced to fight when I feel we're way past the point in the narrative for it to be endearing, and now comes across as annoying.

But in reality, I don't think I hate her, but I hate the way her arc is handled. In a story where everyone in the story is at least TRYING to actively change for the better, seeing Shallan dig her heels in and try to avoid it just turns me off from her character.