Started rewatching Rogue One again last night to try and figure out where they might go with the final arc. One thing that is apparent is that Cassian has spent some amount of time already on Jedha before R1. He knows who Baze and Chirrut are and what conditions are like in the city, etc. So that seems like something they might explore.
It also seems like there has been some kind of break with Saw and the rest of the Alliance that is more profound than anything hinted at to this point. So that could be a focus as well. I’m still mad we never got to see his dudes in any kind of real action. Hopefully that is coming.
As far as the supporting cast, I assume we won’t see Bix again. Not sure about Wilmon, or Vel. They don’t necessarily have to revisit either of them I feel like. Luthen and Kleya and Dedra are really the only characters who seem to need some kind of resolution.
There are so many interesting loose threads that I'm sure will be left unanswered. What happened to "x"? Why didn't we see "x"? There are so many characters that they could be interacting with on Yavin, Coruscant, etc.
I'm kind of glad they've not done a ton of background easter egg stuff - e.g. "paging General Syndulla", that might detract from the serious tone of the show. And I'm also glad they didn't shoehorn in a bunch of random stuff like we saw in The Book of Boba Fett - e.g. how did Boba Fett escape the Sarlacc Pit?
I personally was kind of hoping for a Senator Leia Organa sighting in the senate chambers sitting next to Bail, and I guess we still might, but if its not critical to the plot then it might be more distracting than anything.
Some of these tangents they could probably make a whole mini-series around (animated or live action). A series about Saw's rebels would be sweet, but its probably not central to Andor's plot. Maybe they'll get involved at Gohrman.