Rogue One is my favorite movie.
When I was a kid playing with Star Wars toys, the stories in my head had a look and tone very much like Rogue One and The Mandalorian. Those resonate so strongly with me because it’s like seeing Star Wars the way I’d always imagined it.
I think the problem is the dull characters. Each has an interesting backstory that should make for an interesting character but watching them interact they all looked so bored. Cassian says he’s been in this fight since he was 6 but we don’t learn why. What motivates him to push further and further towards grey morality, in essence becoming as bad as the Empire to fight the Empire? That should be interesting but it’s never explored.
For me, Star Wars requires a lot of inference, and I think that’s one of its strongest attributes. The first movie drops you right in the middle of a war. You have to figure out what’s going on. They don’t explain who Darth Vader is or why he’s wearing a breathing apparatus. There’s a backstory there, but that’s not the focus at that time.
You description of Cassian Andor actually says a lot. Something traumatic, likely Imperial related, impacted him when he was very young and the Rebellion is very personal to him as a result, and we see the extent of that in the grey morality you mentioned.
Same for the “Gun Guy” and the “Force Guy” (yes, I’ve forgotten their names). They say in passing they once thought similarly but have since drifted in beliefs. What motivated that and how will they reconcile? Never explored, instead they just offer Jyn weird advice.
The huge Star Destroyer hovering overhead tells me their worldview was also greatly affected by the Imperial raids of their temple. Chirrut still believes in the Force, but Baze who as you’ve mentioned was once the most devoted of all, no longer believes. Eventually Chirrut walks to the control panel they need and Baze sees how the Force protects him from the Death Troopers. Baze’s belief in the Force is restored before his own demise. I especially love the dialogue of both characters.
Or how about the Pilot? The Pilot is just a walking plot device. He has no characterization other than knowing Imperial stuff. We never learn why he defected or what he believes in, he is just with Galen for whatever reason and knows the tech stuff.
We know a little less about Bodhi, but enough to say his interactions with Galen Erso as a cargo pilot, probably while making deliveries, inspires him to help Galen get his message to Saw. When I think of the Empire, I imagine a lot of people like Bodhi working various jobs who are just caught up in the churn. They’re good people, but feel helpless. They need hope.
“Condense fact from the vapor of nuance.” - Snow Crash
I also think Rogue One has the best space battle in all of Star Wars.