ex- Saw Guerra and his motivations are known from the CLONE WARS; Tarkin was power mad; Krennic as well-the power struggle between them was just more orchestration by Vader and Palpatine . they felt that the best way to run the empire was through conflict between the generals and other military leaders.
the other characters can be found out through some reading. SW CATALYST gives the backstory of the Erso's and Krennic. Just like you guys read the books on THE EXPANSE and know more about the backstory becasue you read them, so too can the same be achieved by reading CATALYST (as one can get info on the backstory of EP 7 from reading the AFTERMATH books)
why do we need to have sappy love stories and whiney boy stories of "daddy left me" to make a "good" SW's movie? I think all prev 7 films have plenty of that
that kind of story would have taken away from the action and the plot of the film. In a way, you can say that most of the R1 squad that initially attacked Scarif were men who knew themselves to be "flat". As the CPT said, they all had made sacrifices and done terrible things for the rebellion, they had no illusions of happy endings and that they wanted a chance to 'redeem' themselves (to themselves?) by taking part in a mission so important
and yes- it IS a war movie, no doubt, it was billed as such. and it was a freaking awesome war movie being set in the SW's arena
and I am glad that it was so built up as an anthology movie--so, no sequels (well there are already 7 sequels aren't there?) no prequels, though there is still plenty of space to tell other stories within the galaxy, the rebellion and the empire; big place, big movements lots of people (over a million imperials staffed the Death Star, so scale of potential players is massive