So I've been watching The Force Awakens today.
I find it interesting that, with the exception of Finn, every character is driven by nostalgia. Han and Leia want their son back. Rey wants her parents back. The entire First Order wants the Empire back. And yet, all of their perceptions of the past are flawed in some way:
Ben wants to project a certain image of Darth Vader but does not understand how it came to be, even stubbornly believing that Darth Vader never went back to the light side at all. He is really seeking a father figure that Luke and Han were not.
Rey wants her parents back, yet stubbornly wishes to believe that her parents didn't abandon her.
Leia and Han want their child back, but Leia in particular seems to hold on a notion that any turning will be similar to how Darth Vader turned (The Last Jedi also plays with this very effectively during the throne room scene).
And in their grief, Leia and Han go back to what they knew best.
Many of the Resistance fighters are driven by the good memories of the old days of the Rebellion, including Leia.
The First Order seeks to emulate the history of the empire, but they don't know their history and as such are doomed to repeat it. The First Order in particular looks at the Empire and thinks it's failures are due to not being brutal enough, and a significant part of it's major players are youths whose only quality for their powerful positions is personal loyalty to the supreme leader. There's probably a parallel in history somewhere there (obligatory reminder that we went from the A7V to the Königstiger in a smaller timeframe then Death Star and Starkiller).
The exception to all of this is Finn, whose primary character motivation is running away. This continues all the way to the end of the Last Jedi, as a suicide, even if it's an heroic suicide charge, is an escape from things.
So almost every character in TFA is interested in reconstructing a flawed understanding of the past, whilst TLJ is interested in deconstructing it. There's a nice thematic line going on there, with Episode 9 firmly setting its sights on creating something.
What I am also noting is that TFA is a far more simple film, and in some ways TLJ should have picked up a bit on that. In TFA, a few new and old heroes go to starkiller base
1) to blow up something up
2) So that the starkiller base can be shot at
3) which they know about because Finn was a janitor on the base
TLJ's tech-breaking plot involves
1) Going to a casino planet
2) To find a shield breaker
3) who can get them onto an empire vessel
4) to disable a tracking device
5) that needs to be disabled rather then destroyed
6) because the Empire can track ships trough subspace
7) But only one ship at the time
8) and they need to be unaware that they've lost that ability
9) because other ships can also do it but don't because reasons
This in turn leads them trough all sorts of different plot points involving red herrings and a simple level of moral greyness in the mind of a mercenary, but it's unnecisarely convuluted in a way that doesn't allow any of that to shine because they're spending a lot of time on detail-based sci-fi and returning a character from TFA purely for exposition purposes.