Yes, Judderman, this is almost pure nostalgia. I can't deny that. All the things I loved about it were all the things I loved about the original trilogy. X-wings! Y-wings! AT-STs! AT-ATs! Space battles! Ground battles! Interesting aliens! Different worlds! But while TFA was just an unashamed rehash of A New Hope, I thought this was something different - this was its own film that happened to inhabit the same universe. Granted, it still tied heavily into ANH, but at least there wasn't a Skywalker in sight! (Alright, one. But only briefly.)
Okay, so some tropes got re-hashed. But I thought the father-daughter dynamic served the story well here. And it added in a nice layer to the existing mythos and neatly papered over something of a plot-hole. Why was there such an obvious, undiscovered flaw in this amazing technological marvel that is the Death Star? Now we know.
I also appreciated the tone of this film. It dealt a lot more with the gray areas that the previous films tended to shy away from. The Empire Strikes Back is often cited as the darkest of the films, but even so it still knows who is a good guy and who is a bad guy (Lando is about the only character who wavers between these extremes, and even then he's more roguish than evil). Rogue One, on the other hand, introduces us to Cassian by showing him coldly shoot an informant. This is a guy who's done - and is willing to do - some questionable things for his beliefs. Jyn is similarly conflicted. Unlike Luke and Rey, it takes some convincing for her to fully commit to the cause; for the first half of the film, she's pretty much just out for herself. I thought they both did wonderful jobs with their characters.
The supporting characters were all strong and showed a good amount of depth for such. K2 was the main scene stealer, but he only just beat out Chirrut. Krennic was an adequate foe - maybe not as menacing as I'd hoped he'd prove, but he still embodied that imperious Imperialness perfectly. Vader's involvement was measured and benefited from being so. Tarkin... well, more on Tarkin in a moment. I enjoyed the time spent with the Alliance council as well, and it was particularly nice seeing Bail Organa involved. Again, it gave a little more depth to things we already knew, without hitting us over the head in the way TFA was often guilty of.
I thought the overall structure and the last act in particular were really well-handled, given the constraints inherent in the story - we know this mission succeeds, so there's not a lot of tension in that regard, but they crafted a story that had a lot of tension despite this. They made us (me, at least) care about the characters, and then threw them into what seemed like an unwinnable situation, and had them win the day in a believably, if costly, fashion.
The action scenes were brilliant - so much better than TFA. Again and again, I find myself wishing that they'd given that movie to Gareth Edwards to shoot. For mine the final assault on Scarif rivals the Battle of Endor in scope and execution as the best of series to date. I loved how they cut in Red and Gold Leader footage from ANH - as I was watching I thought that they had just done an amazing job of re-casting, and didn't discover the truth until afterwards. I also thought it did a nice job of explaining why the Rebel defense of Yavin was a little thin on in ANH - most of the fleet had just recently been decimated.
My one complaint with the film has to be Tarkin. The CG was good, but not convincing enough for such a prominent role. I just found myself distracted by that every time he appeared. And I feel like it could so easily have been avoided. The first couple of times he appears, have it be via hologram. The next time, have him keep his back to Krennic and let us (and Krennic, as an insult) only see his face only as a reflection on the glass of the viewport. Then reveal him - still briefly - as he finally takes command of the Death Star. The brief shot of Leia worked so much better, because it was brief.
Overall, that's a minor quibble. I had a great time. Was it a necessary film? Probably not, but what film is? Will it get new fans in? Maybe not, but wasn't that the idea behind TFA? Did it break new ground? Yeah, a little. It was a Star Wars film that didn't shoehorn in Skywalkers, Solos, or unlikely relatives of Skywalkers and Solos. It was a Star Wars film that was about war and the dirty, disagreeable things that people rebelling against an oppressor might need to do. It was a Star Wars film that felt so familiar, but that did it's own thing.