I think a lot of people are, subconsciously, succumbing to exactly the problem this movie strives to address: scope creep.
This movie does exactly what it needs to to deliver a two-and-a-bit hour emotionally driven narrative with good characters, relying significantly more on performances and visuals than on complex world building or prior experience with a franchise.
I've seen criticisms from many about the pacing, lack of explanation for the state of the world, no asking of "how did we get here" and so on.
Do you really need that? The premise of the film establishes a core relationship between the main character and his wife, and introduces an internal conflict at the heart of that main character. The film addresses it over the course of the film while external forces fight over the fate of a people whose whole existence reflects the internal conflict of the main character. The main emotional through-line of the movie is perfectly tied to the world. We don't need to see the entire tapestry of history to understand that.
See the movie and come to your own conclusions. It's not a franchise film, and there are unanswered questions about the setting. None of that should compromise your understanding or enjoyment of a good, emotional, character driven story with excellent visuals and great performances (especially Alphie! Wow, she's great).
I look forward to seeing what Gareth Edwards does next, and good lord, not everything needs a sequel. This movie stands tall on its own, and its world doesn't *need* any further context or development.