I think the plot maybe would've been more straight forward if ...

- Jyn's mom is killed, but she thinks her father has abandoned her for the Imperials.
- She grows up a "rogue" nobody (no pun intended) who's a smuggler or something
- The Rebel characters (all of them) get in contact with her because they want her for a big pay day mission: her dad is alive and he's helping the Imperials build the Death Star. They want her to help them get to him and she's promised a big pay.
- When she's reunited with her dad, she realizes he was forced to work against his will and he never tried to contact her for fear the Imperials would kill her. He's created a weakness is the Death Star to be exploited. 
- Seeing her father's sacrifice, she agrees to join the Rebellion.
- Second half of the movie plays out more or less the same, but I'd give Vader a little extra few bits and have less emphasis on pushing levers/buttons (that got kinda old). 

Something like that I guess. The first half with trying to find Forest Whitaker's character to find the father character was kinda all over the place, I think it would've worked better to get the "team" of Rebels together earlier on in the movie so they had more time to gel.