So, there seems to be two main points that the real haters are focusing on.
- Fanfiction 2) SJW propaganda.
Now, I do believe these are both reactions to, well, The Force Awakens. The first just being a hatred for Rey, who was a Mary Sue and one that gave the entire movie a fanfiction feel.
And where that is true for The Force Awakens, its not Rogue One, at least it is not Rogue One if we are staying in the Star Wars universe...it COULD be fanfiction if someone warped Saving Private Ryan into the Star Wars universe and...yeah, not, It's not fan fiction.
The Second point, the SJW one, well, that could honestly also be a backlash against The Force Awakens as, yeah, anyone that called Rey a Mary Sue was accused of being a misogynist for, well...reasons.
Specifically for reasons that had NOTHING to do with why they didn't like Rey--at least why most people didn't like her...most.
And, in Rogue One, if the cast is multi-cultural of ominous political agenda reasons...it doesn't really feel that way. The diversity works and it works because you don't really notice it unless people point it out to complain about it..
...and the people that do, yeah, it is likely because of The Force Awakens and they are forgetting that this takes place in a Galaxy Far, Far Away and, well, by definition they are all aliens anyway, so, you know, trying to force diversity in a movie entirely comprised of according to Hoyle aliens...wouldn't that mean a LOT more alien looking aliens? So, a lot of that is lingering from The Force Awakens and, well, some of it is understandable, if not for the movie itself than because of the backlash against people that thought Rey was entirely too perfect.
Another reason for that hate could be a lack of lightsaber battles and, I really feel the fanboys on this one...but, no, really this was a Star Wars movie that felt like a war movie and the lack of blatant force powers and lightsabers until the very end worked...
In fact it worked so well you did kind of get a Saving Private Ryan feel off the movie, a lone rogue squad taking on the entire Nazi?...Sith?...the entire Intergalactic Empire.
It was really fun to watch and, not sense the Evacuation at Dunkirk that was the planet Hoth, did we see a Star Wars ground battle that really looked like it was a war. So this was pretty cool.
And then there is Jyn. Now a lot of hate gores to her and I can't figure out why. She seemed like a real character. Rey could have been a feminist SJW transplant that was made super awesome because...reasons. But Jyn had serious flaws, she had issues, she seemed like a real person. So props to Felicity Jones for bringing that awesomeness to life.
No, seriously, props to her. Outside of Solo, I really don't think I've seen a Star Wars character I thought was that, well, cool, real, just fun in the way that you could point to her and say "I could know someone like that." There were other cool characters in the saga...but none as realistically portrayed. And that doesn't just go for Jones.
The only main character that doesn't seem like a real person was Chirrut Îmwe and, well, we can forgive him for that because he was the kung-fu movie awesome that helped make the movie not just a war movie in space. He was the guy that brought the Force into the film and made it a Star Wars flick...so, who really cares if he doesn't feel like a real person? I know I don't.
And the last bit of hate is because, well, it doesn't have any of the real main characters, no Solo, no Skywalker and...well...it IS a stand alone movie, so if you came in expecting them, well, that is your fault. Disney made it clear from the get-go.
What you have here is a cool science fiction war movie. It fits into the saga and it doesn't, but that isn't a bad thing--prequels, the Force Awakens--as only 3/7th of the saga movies are really any good.
And, as a war movie, it stands on its own. It is actually better than a LOT of the war movies people tout as masterpieces cough Thin Red Line cough So, watch it, you should have no complaints...
...unless you are complaining about the SJW, the Fanfiction, and the lack of Skywalker or Solo, and if you are, well, there is going to be no pleasing you no matter what you watch.