As for Leia pulling herself out of space... I basically just wrote an essay about this and it digressed at some point. So I'll split this into two things. First, about Leia:
this movie rebuilds what it means to be a jedi in a way that needed to happen. George Lucas never understood his own universe; the the original trilogy's construction of what a jedi is gets shat on in the prequels and most supplemental materials.
The light side protects, the dark side destroys. The light side warns of danger, the dark reveals your enemies. The light decieves to avoid violence, the dark decieves to entrap one’s enemies.
People have pointed out in the prequels that the jedi don’t act like jedi. This is because they do nothing but fight and kill, because George Lucas puts too much stake on his own icons (in this case, he thought the lightsaber was what defined a jedi simply because the lightsaber is what the fans latched on to). This is also the sin of the extended universe and why I’ve always dislike it. The EU practically masturbated to OT icons. The deathstar was rebuilt and redisgned endlessly. Palpatine came back to life a billion times, be it through a secret apprentice, literally being cloned, or through expies. Force users and lightsabers were ubiquitos. To say nothing of the undo importance given to the core trio even tho in universe they’re not *that* big a deal and Star Wars has so much room for other stories. I’d go on but this is a digression.
Going back to what a jedi is: Obi Wan did jack shit with his lightsaber. He protected Luke once because Luke wasn't tough enough guy for the cantina, and he distracted Darth Vader for about 5 minutes. In all other ways he used the force and his wits. Yoda never accomplished anything with his lightsaber. The only time Luke used his lightsaber and it actually helped him, was when he threw it away. All other times he could have used a blaster or, again, he was just delaying Darth Vader. And it was heavily implied that Vader only had a saber because he was a fallen jedi, an implication that the new trilogy holds to.
The lightsaber was a symbol of the jedi, not the core of their power. The core came from the force. But the jedi never use the force to cause direct harm (outside the prequels), hence why they carry physical weapons. Also why Palpatine had no respect for the lightsaber. Palpatine probably could have snapped Luke’s neck whenever he wanted or stopped his heart, he used force lightning not as some kind of MOBA ultimate, but because it inflicts a torturous and slow death. The new movie also held to that implication. Palpatine spent his last moments fruitlessly spewing lightning everywhere because he’s a wretched old man with dark magic fueled by negative emotion. Hurting people is all he knows how to do. It would have made no narrative sense for him to lift himself out of that pit.
Okay, that was all discussing the OT. Now back to TLJ. All plotlines in TLJ are built around a single narrative thrust: "do we need a hero, and if so, what is a hero?" To this end the movie even questions whether the galaxy needs jedi to fight sith and a resistance to fight the first order (the answer is "yes" obviously, but its noteworthy the movie went there). Each member of the core trio gets their own narrative thread, and each reaches the same conclusion via different means: "being a hero means helping the people you love, not hurting the people you hate." Rey has the most interesting plotline because Rey reaches this conclusion way earlier than the others, about halfway through the movie when she realizes that her and Kylo share something in common. The rest of the movie isn't spent on her learning that lesson, its spent rebuilding her into a new Jedi after she rejects Luke's mentorship. Luke was the first person to ever learn this lesson, as he went into his final battle not to kill the emperor but to save Vader. Luke's failure was not in being a hateful, violent, absolutist prequel jedi (which is what Rey *thought* a jedi was). Rather Luke's failure was giving up. Much like Luke took the good parts of Yoda's teachings and replaced the one part he didn't like ("let go of your friends") with his own new truth, Rey takes that core kernel of Luke's belief (pretty much the only thing he *does* teach her) and becomes a new Jedi without the rest of the trappings.
We see what this new Jedi means first when she and Kylo physically rip her lightsaber in half with the force, destroying it beyond any possibility of repair. She goes the rest of the movie with no lightsaber, in the first SW movie with no true lightsaber duel at any point. Then we get a hint of what this new Jedi is when Luke defeats Kylo Ren using only the force, without harming him in any way. Not only does he not physically harm Kylo (remember, he did have an X-wing, he could have showed up), but he doesn't give him the uncertainty of the truth that he only meant to kill Kylo for a brief second, nor does he give Kylo the guilt that would come with killing Luke. He entered that final fight having let go of his failure, and as a result he is able to confront Kylo content in the knowledge that the fight isn't about his old student but rather about the galaxy, Leia, and his new student. The finally we see it in full at the end of the movie, when Rey lifts the rocks out of the way so the resistance can finally escape. That's what a new-school jedi is. Not someone who says "1v1 me bro" to the main sith at the end of the movie.
And that is why Leia is able to pull herself out of space. She's not a jedi at all, she's just a force sensitive who taps into the light side, much like that one dude from Rogue One. All she uses the force for is to check up on her elderly friends dying, do some fortune telling on the side, and to save her own life when the resistance still needs her. Because she has no illusion that the force is her weapon (rather relying on her fleet, allies, and blaster), she doesn't need to learn the lesson that brought down the prequel jedi. Thus, Leia is using the light side its most proper way, to save a life and to guide others towards the right path. Hence why something that might have been very difficult for the powerful dark side users we saw in the OT, she makes look easy. It also can be inferred that with skywalker blood Leia is a very powerful force user. She seems to have a strong understanding of the light side, just in a wise old lady way, not a jedi way.
As I said above, TLJ was about among other things Rey learning a core lesson about the force. But the first piece of that lesson we see isn't from a jedi, its from Snoke. "Destroy the past." Luke and Rey entered the movie as terrible jedi because they thought they had to be an old jedi, a prequel jedi. Rey comes one step short of saying it. If you'll let me twist one of her quotes a tad, "the force is a power the jedi use to fight bad guys." No, of course not. Big bad guys exist and they always will because the force has a dark side as well as a light. To be a new school jedi like Luke tried to be and Rey became doesn't mean fighting the sith. It means not giving a shit about the sith except to pity them. The prequel jedi, and in a better written way yoda and obi-wan, they hated and feared the sith. That was the seed of their destruction. Fear and hate are not the way of the light side.
As part of this journey, we destroy the images of the sith and the empire. Vader's mask, the single most important icon in Star Wars history, is 100% absent. Its destroyed in effigy by Vader's whiney, contemptible replacement that no one is afraid of. The empire is destroyed when its geometrically shaped super weapons are destroyed twice with little effort, like they always are. The gruff dreadnought commander goes scowling into the fire, leaving Raeh, the only notable imperial commander we see for the entire film. A thin, man, squabbling but competent, not particularly evil, who gets tossed around like a ragdoll by the force all movie. Again, someone no one is afraid of. Palpatine is destroyed when his expy is cut in half, his person honor guard killed, his throne room burned down. All this left is Kylo, and Kylo lacks the one thing both the Emperor and Snokes had in spades: self-confidence. He's never going to truly replace the emporer. The semi-competent, mundane-evil imperial officers are never going to break lose of the sith, and they're never going to catch the rebels or defeat the jedi.
At the end of the movie, the square-one journey of The Force Awakens is complete. The larger rebellion is left ambigious, the rebels but a small group, the empire and sith control the galaxy and only one jedi is left. We're back to the OT. Yet, we end on a note not of pity but of happiness for the devastated rebels and jedi, because they are reunited with their friends and they've been freed to start a new adventure. And tho the sith and their empire are still the galaxy dominating superpower and evil as ever, we end on a note not of menace, of hating and fearing them, but on pity. "Destroy the past." These words resound throughout the movie. Star Wars isn't destroyed, the war isn't over and the adventure isn't either. But cultural icons were killed symbolically. This is what the hardcore Star Wars fans, and the EU fans especially, hate about this movie. They've been extrapolating what SW is not from its setting but from its icons. To them SW is the lightsaber, its Darth Vader, its the original trilogy of heroes. This movie extracts the beating heart of what SW is, and cuts away the rotten flesh that was the icons. In doing so, those hardcore fans are left behind because their version of SW doesn't exist. The Han Solo movie is likely to be the last hurrah of that SW. Everything else is new territory. But the hardcore fans are wrong to throw up a stink, because they're claiming ownership of something that was never theirs to begin with. SW may have helped define geek culture but its not a geek thing. It was never niche. Pretty much any white dude over the age of 35 is a SW fan, the young fans are less numerous but more enthusiastic and diverse, the SW fandom is just "the USA" at this point. I'm pretty sure more people like SW than baseball. To me, SW is a classic piece of Americana, if any fans have ownership of the franchise (which is a fallacy unto itself), its American moviegoers as a whole. Some guy who's personally written 300 Wookiepedia articles owns the franchise no more than some random smuck on the street that watches three movies a year. And to me quoting SW facts about how fast the millennium falcon can go or whether Vader would beat Maul in a cage match, reaks to me of fandom gatekeeping.
This movie needed to happen. If the prequels are to remain canon yet be redeemed so they don't keep hurting the story, we need to canonnically move away from the prequel jedi (and by extension, the EU + video game jedi that have more in common with prequel jedi than they do OT jedi). And for OT obi wan and yoda to be redeemed, we needed to finally address the flaw in their teachings, which is that one stupid "here's an absolutist speech about why absolutism is bad", and that other speech about how hatred is bad that's why we hate the sith. In this way the OT too, is redeemed, in a way I never realized it needed to be. Finally, the seventh movie is redeemed from it existential worthlessness. The work that the heroes did in the OT was effectively undone halfway through The Force Awakens. As a result it essentially rebooted the franchise just to tell a the same old story. Its cool that we got a new SW but it didn't need to exist. The new director for TLJ had the choice of following the arc of the previous movie, or choosing to turn things around and have Luke and the New Republic not be completely dead. Instead, the director chose to continue the path of The Force Awakens to its logical conclusion were all the fighting Luke, Leia and Han had put in has been erased. Instead, their victory is a personal and moral one, as each guides the next generation of the galaxy to greatness in a different way. In this way episode VII is redeemed: what was an unintentional middle finger to the OT now reads like part of a two movie love letter to everything the OT was. Because IMO while it cut away the icons TLJ *got* SW on a deep level. What made it for me, and the final way that it redeemed the previous movies (prequels this time), was that it created a universe in which ordinary people could make a difference. A little kid, a kangaroo race horse thing, an arms dealer, random rebels. Hell, a BB8 spray painted black gets to have its moment and be a weirdly menacing character. The OT was always like this; but the prequel trilogy, with its inescapable destiny and lack of any obvious Han Solo character to balance out the royalty and jedi, took this away and made people forget what SW is really about. To me TLJ is a triumphant return to form.
The most destructive thing the movie did to the franchise IMO is that it destroyed without creating. The story could go anywhere from here. By declawing the main bad guys a bit and leaving Rey with no obvious next step, plus establishing that the new trilogy can be its own thing now, TLJ leaves the next movie with a lot of freedom but also a difficult task. Whatever comes next is going to have to build a new identity for the "main line" Star Wars franchise. Not even for any hypothetical fourth trilogy; rather, for itself, as the new trilogy has been left intentionally rudderless. Personally, I don't think the next movie will succeed in this task. I think the next movie is going to see the conflict to its logical conclusion: Rey will kill or redeem Kylo Ren, the resistance will defeat the first Order or at least one of their fleets/super weapons/bases. I expect JJ Abrams to go back on some of the changes that TLJ made to the franchise and to his own plotline, but I think the changes to the franchise from TLJ will ultimately stick. If nothing else because Rian Johnson is going to make more movies in the franchise. I for one am excited to see where things go! No more rules now. No more prophesies, no more skywalkers. No more limits about how many force users exist in canon.