possibly a controversial opinion but I’m gonna be honest: Shallan got nowhere near as character development as Kaladin and Dalinar. Even in her own books she gets less flashbacks and scenes, and the development she does get can summed up by ‘reckless girl who thinks she’s shy stays just as reckless and decides she is less shy’. Its told not shown.
Shallan thinks constantly about how she’s gotten less timid but pretty much the first thing we see her do is demand that a princess teach her so even if she has progressed it doesn’t feel like it when you read the books. (Her ‘new’ boldness also mainly takes the form of her ordering darkeyes around which doesn’t exactly give a good impression of her, but that’s a post for another day.)
A possible reason Shallan’s development feels so inefficient is that compared to Kaladin’s and to Dalinar’s, anything would be. They grow and change while she just flickers between acting brave and like a Modest Vorin Lady. The two of them have their values examined and changed while Shallan stays, well… bigoted. She’s far behind where they even started off.
Unfortunately it could also be because both of them interact with lots of people who they aren’t attracted or attractive to, a privilege Shallan doesn’t get. I personally think the plotline with Kabsal would have been just as effective had it not been for the romantic aspect and it might have stopped me feeling like Shallan always end up pigeon holed as a love interest, developing relationships with other characters rather than personality traits of her own.
And of course, what actually constitutes a ‘personality trait’ is a little more complicated with Shallan. What does development even mean for her? She decides she’ll be more bold from now on? She adds a new aspect to her fake personality? She changes how she thinks of herself and doesn’t alter her pretend self?
I’ll admit Shallan does grow more open to unladylike behaviour, if only because of the addition of her Veil persona. (And to be honest her overly proper views also felt a little like a performance, as I’m sure they’re intended to). That said I’m still frustrated she got so little development compared to other characters.
(Especially since Words of Radiance was meant to be her book, not Kal or Dalinar’s)