Of course, most people think of Atticus Finch when they think of To Kill a Mockingbird, and with good reason. It's rare for pacifism to be portrayed so lovingly. Particularly nowadays where every hero or superhero has to be a badass or a smartass. Atticus isn't just Lee's endorsement of the principle of non-violence, of care in discourse, and reason before retribution. She shows how really beautiful it can be; particularly in a world that can be quite ugly.
I haven't read the recently released Go Set a Watchman. Maybe I will at some point but like many people I have suspicions about the legitimacy of its publication. I think there's at least an 80% chance it was published against her will or without her fully cognisant knowledge. I don't like reading works by authors that the authors don't want me to read. I'd agree there's an anthropological interest in the idea. We might indeed learn something valuable if some poetry by James I were discovered and read even if he never wanted these poems read. Looking at earlier drafts of an artist's works can reveal interesting things about their process and reveal something more about their intentions in the choices they made and in things they rejected. But knowledge of these things inevitably alters the impression of the work itself for that very reason. Sometimes insight isn't a good thing when it might narrow the scope of the work. This was J.R.R. Tolkien's complaint against allegory, that it narrows the possibilities of a work of art. When an author permits "behind the scenes" information to be published, that's part of the art as it's part of the expression. When talking about jazz, people talk about how the notes that aren't played are as important as those that are. The mind's unfulfilled expectation of a note is part of what shapes the mind's reaction to the piece as a whole.
I used to go to great pains to explain this kind of thing when introducing a David Lynch film to someone. Lynch uses silence so that he can punctuate it with sound. It's particularly evident in the first act of Lost Highway. The compulsion of the average viewer is to fill up every moment, to squeeze in every piece of trivia, rather than allow themselves to feel the tension. Though fortunately I think the legacy of the short song called To Kill a Mockingbird drowns out anything else. The simplicity of its statement on human nature is just too eloquent.