I said this in the other Rogue One thread:
They're very different films. They do different things well and has different aims. TFA was meant to bring back Star Wars for a mainstream audience. RO is meant to show how flexible the concept and universe is.
I think they both succeed and which one you enjoy depends on what you want out of Star Wars.
TFA creates a strong emotional connection to the involved characters. RO is more about their mission and the overall meaning of that sacrifice. TFA is about Rey and Finn. RO is about the Rebellion and its third act tension is seeing everyone pitch in against overwhelming odds.
I don't fault those that preferred one to the other. I think RO has one if the strongest third acts on the franchise.
To use an Extended Universe example, some prefer the Rogue Squadron books to something like Traitor or the rest of the New Jedi Order. Different story types.
TFA is all about the fact that you want to be on a journey with these characters. What happens if less important than how they react to what happens. If you don't connect with them, the movie will fall apart for you.
RO is about the mission and the losses required to make that work, which is why the third act works. It commits to the death and desperation of soldiers, just to beam some data into orbit. It's nearly a heist film, in that everyone fills in their predetermined slot. They do what's need to and then they die. You don't necessarily need to know the characters, because the mission is the point.
When RO falters is in missed opportunities and lost characterization. Everyone is a bit of a cypher with rather board motivations.
Like Jyn's turn to heroism isn't really the fact that she believes in the cause now, it's that getting that data to the Rebellion justifies the entire craphole that was her life. She's searching for meaning. If the Rebellion has the Death Star plans and destroys the station, than the fact that her dad defected, her parents died, and she was left a wartorn orphan all matters. It wasn't the universe being shitty, it all lead up to that moment. But they never really dive into that on film. (The closest they get is when the castoffs say 'Without this, everything we did was just evil shit.")
I think they're both great films. Just with different needs and central points. Some people will like one more than the other, because they want different things out of the franchise.
In a universe where advanced, human-intelligence, sarcastic robots can be created, the giant tower of important engineering data has a human-driven arm. Careful manual operation is required to send this claw thing up and manually select the SUPER IMPORTANT VALUABLE DATA TAPE. What if it's on the back side of the tower and a pain to see? Why is there manual control at all? Maybe it's supposed to be an emergency backup and they didn't know about automatic control, even though K-2SO was hooked into the system and knew exactly where the target tape was.
I'd argue that Star Wars as a whole is a series of contrivances in the name of in-the-moment drama. Not the best answer, but it's true. As a further example in RO, why is the alignment model out on a catwalk? Because it's more dramatic for Jyn to have to go out there to fix the dish.