The human CG (Tarkin, Leia, Red Leader) was amazing. It was still mostly obvious, but I would place it (just barely) on the far side of the so-called uncanny valley, meaning that it was good enough that if you wished, you could suspend belief just as we normally do with all the other fantastical visual elements.
As for my major beef, it's the utter absurdity of Tarkin ordering the destruction of the base on Scarif. First, this was an expensive Imperial outpost with a level of security we'd never encountered before. Speaking of which, if it's possible to put a planet-wide force field around an Earth-gravity sized planet, it raises the question of why they didn't have a similar shield around the Death Star itself? Or at least the new Death Star, after the first one proved to be vulnerable. Bam, rebels thwarted! Anyway, back to Scarif, it seemed like a cushy assignment. One would think that there might be a few family members of high-ranking Imperials stationed there, and as such, an order to vaporize one's own base wouldn't just fall to the whim of one man, even if he is a Grand Moff. It's like if you get a bit of poison ivy and your doctor decides to amputate your arm, can we at least talk about this first? Second, the logic of "we can't let those plans escape, at any cost, even if it means destroying the entire base" doesn't make sense in terms of Tarkin's character. As we saw in ANH, he confidently believed the Death Star to be utterly impregnable. So what if the plans were stolen? On the other hand, if he did think the blueprints had some risk of revealing weakness so severe that they were worth destroying a major outpost over, then why didn't they order a top-to-bottom review of the Death Star's vulnerabilities before they put it into full operation? There was no evidence of that having happened in ANH. Finally, we're meant to think that Scarif was a one-of-a-kind repository for all types of military blueprints and whatnot. Supposedly the rebels had to break into that nigh-impossible-to-break-into location because that was the ONLY place the Death Star plans were located, along with thousands of other sensitive documents. It was vital to the Empire. If so, destroying the location would effectively be performing the rebels' work for them. It makes no sense, except in terms of making it impossible for any of the Rogue One heroes to have survived (which I was totally unprepared for). Superficially that felt like a bold narrative choice, killing off the main characters, deliberately closing off any avenues for their stories continuing (except see below). But because it lacked logical cohesion, it came off to me as a bit of a cheap shot. Besides, this is Star Wars. So what if you can't make "sequels." You can still make prequels, sidequels, reboots etc., and the knowledge of that means that for us as viewers the shock of a permadeath is necessarily blunted.
The destruction of the colony on Jedha is similarly illogical. To test your new superweapon, you're going to destroy a major Imperial kyber crystal mining facility, as opposed to some random deserted area? "Haha I'm so bad-assed I just stabbed myself in the eye!" Okey-dokey Tarkie. (Narratively it served function of killing off Saw Gerrera. But he came off as unlikeable anyway. He was even distrusted by the woman he raised from childhood. (Do all adult relationships in the Star Wars universe have to be marred by distrust and betrayal?) So who cared about him except for hardcore uberfans who stanned a minor character from the Clone Wars animated series?)
Anyway, that aside, I really liked K-2SO's character. This is the first time we've seen a droid who's that limber and kinetic, and intellectually equal to his human counterparts. Droids are usually either incapable of speech or have deliberately stunted personalities so as to sidestep the ethics of droid slavery, but Kaytoo was a full-fledged person. I would describe him as an improvement in every respect over C-3PO. His death was the most heartbreaking part of the film but it occurred to me that technically he could've uploaded his personality matrix into the Scarif mainframe, and wrapped it inside executable code that would attach itself to the transmission of the Death Star plans, thus surviving the destruction of the Scarif base. That would explain why this selfish character would suddenly and uncharacteristically be willing to sacrifice his life for the greater good. His resurrection would totally ruin the dramatic value of his demise but hey, theme park money, so maybe somebody ought to suggest that to Disney.