I felt the characters were sufficiently developed for their various purposes within the movie. We spend as much time with them as we do LUKE/LEIA/HAN in ANH.
What exactly do we learn about Chirrut Îmwe, Baze and Bodhi Rook other than the templates for their characters? Not much…Can’t say the same for Luke, Han, Leia, Rey, Finn and Kylo Ren.
Why do people insist on asking questions like this?
What do you learn about Luke Skywalker?
Are you serious? Luke Skywalker is a farm boy who hates his existence mostly due to the fact that a lot of his friends have gone on to join the Rebellion. He wants a better life but of course is tied to the moisture farm which indicates that Luke is fiercely loyal. I mean I can keep on going but do I really need to?
Not much but you go on a journey with him that is about it and he has 3 films as the main character. If you were expecting a historical epic about someone you will not find it in Star Wars films.
You must not be watching the same films I do.