I really like trying to build more RPG into IA. The problem is that to some extent, it is hard to be purely creative (like you might in an RPG) since most of the characters have some sort of backstory that is weaved into the side missions. I think it'd be really cool to have a sourcebook (for the IP) for IA that delves into: 1) more background (for the IP) regarding the story and villains, 2) the Hero backgrounds, 3) information about some of the planets that we visit (the Ison system comes to mind) 4) suggestions for further developing the RPG aspect.

I've thought about buying the Age of Rebellion core rulebook (I have the Starter game) to use as a guide but I'm not sure how helpful it'd be.

I think in my next campaign I'm going to encourage my players to invent their own backstories. I also plan to build some sub narratives with the villains that I play. I also like the suggestions in RPG to use the improv phrase "Yes, but" to allow the players to be part of the narrative.

Any thoughts on how to make this game more RPG?

Would you like an IA sourcebook and what would it look like?

Of course the app might abolish the IP so maybe player handbooks would be better?

Well, the Fantasy Flight Star Wars RPG system is meant to be an RPG, and Imperial Assault isn't really designed with that in mind, I don't think. Maybe you'd find the balance you're looking for by playing Age of Rebellion with the maps/miniatures from Imperial Assault?

I think that would be much easier than modifying Imperial Assault rules, and trying to make changes that everyone can agree on.