Star Wars will always basically be the most loved/nitpicked movies.
For those complaining about the plot, what more could they have done in that area really? As far as I know it was pretty close to the material it was using.
The "plot" of Rogue One is so much better than TFA; the former is well structured, cohesive and overall justified, while the latter is an unjustified mess moved forward with ass-pulls and emotional crits that hopes the breakneck pace will encourage people to not notice.
Without getting into too much detail, the problem with Rogue One is two fold: first, it seems that pretty much everything the movie tries to do is just one scene short of greatness. Cassian has some sort of psyche, but it's not exactly crystal clear what that is. Jyn has some sort of relationship with her father, again it's not fabulously apparent why this is so important to her (especially since she gives ****-all when Forrest Whitaker returns to his home planet). Donnie Yen's death scene is played like a guy who lost his faith in the Force and is now taking a chance with it again, but that lost-faith scene never occurred. Etc, etc.
Second, it's just not clever, which is why "generic" is a good way to describe it, rather than "bad". Here's an example:
Without going into everything happening in that scene (like how Han's brash confidence from Empire was replaced with restrained optimism), the scene creates tension, first by creating doubt in the cockpit; by reinforcing that doubt by the Imperial officer noting they're "older codes"; third by Luke and Vadar realizing the presence of the other, thus opening the option that they will be
captured upon detection rather than blown to smithereens. We know the latter won't happen, but the former is very possible- meaning it builds and builds up the tension until they finally get through.
Vs the scene in ROgue One...I don't even remember, it's just "Here are the codes!" and zoop! they're on the planet. Not inventive in the least.