Yes. Cassian’s character is well defined but he doesn’t go anywhere. There’s nothing wrong with a monolithic character, but when you set up questions about a characters ethics and create interesting conflicts for their way of doing things, you can’t just botch the landing by putting that all aside and not saying anything meaningful. He doesn’t have to change to be interesting, but resolving his arc with “I have to help you Jyn because I wouldn’t be able to live with myself if I didn’t” is just a short cut cop out of a more thought out resolution.

If you don’t understand or like Rey’s character, too bad for you. But her story is much more fully formed.