There are some things I think could have been tweaked. Not to suggest it should have been done or is even better, but more just having fun with story and plot ideas.
It might have been cool to see Chewie fire at Kylo, Kylo stop it a few feet away from him similar to the beginning of the movie but "closer call" only to have the bolt go RPG in midair and cause the damage that way. Maybe even create some facial damage right then and there. Maybe even cause massive shockwave damage to his extended arm, making him fight Rey with his less dominant hand.
Another problem I hear a lot is that people didn't feel the same tension with the Death Star reboot as the original. Part of the problem is the rush to come up with the plan at the Resistance Base. The other part is as much as fans love Poe, it wasn't the same as fearing for Luke, Solo, Leia or Chewie's life that were more fully developed in the original Star Wars. There is also the problem that everybody knew the attack was going to be successful.
So some minor reworking of the same elements. Maybe the movie starts with the crawl talking about The Republic flourishing but at odds with Leia's Resistance. The Republic feels fighting a now decimated Empire down to its last remnants is counterproductive and creating more Republic enemies than saving them. (Sound familiar?) The crawl ends with The Resistance having just secured another planet from Imperial Remnants.
Unnamed planet, Leia getting on a ship as she tells the planet’s ruling government they are now free and encourages them to rejoin the Republic. Maybe some talk about the missing Rebel Alliance hero, Luke Skywalker and Leia saying something like “he’s done enough. With the light at the end of the tunnel near, he doesn’t need to be a war hero any longer.” A sister covering for her gone rogue brother.
No sooner than Leia and most (but not all) of the Reistance fighters leave the planet, we see the dreaded (but unknown to the Republic, Resistance or viewer) Starkiller blast vaporize the recently *freed* planet.
This is the equivalent to the A New Hope “holy crap. Look at that ship” Star Destroyer moment. It takes the viewer from “so this is going to be about the New Republic setting up the Old Republic again. Borin …. Holy Crap!!!” Moment out of nowhere. It also sets up an immediate threat that hadn’t been seen in 30 years.
Leia now has a serious reason to find Luke. After years of success, in an instant she feels small and in need of help. Go find ‘em Poe. Similar TFA story to follow except:
Like a terrorist, The First Order makes themselves known claiming responsibility. Pointing out the aggressive moves of Leia’s Resistance not honoring the Republic-Empire truce. Declares war on the Resistance, but not on the Republic. The First Order names its second target. The Resistance base. The Republic blames Leia’s Resistance. “We told you that you were playing with fire. You need to go back to the Senator/Diplomat of your youth and fix this.”
She doesn’t. Instead, very early on (rush attack fixed) they work on how to destroy Starkiller Base. The other parts of the story are mainly kept in tact. Those arcs don’t change all that much.
Fast forward to the ending battle led up to as before. Chewie RPG goes off as said before. Chewie pushes the detonator and … incomplete explosion. Han did not finish setting his explosives because he was sidetracked by Kylo Ben. Chewie is a sitting duck, so Rey and Finn don’t run, but try to help him with the other detonators then escape. Lightsaber battle begins inside SKB. Intense battle, even moving out into the snow (as they are trying to escape to the Falcon – and we get the cool saber snow effects). Finn starts, but Rey saves him, just like before. She also does pretty well against a blast damaged, broken arm Ren. We expect them to pull it off but instead, SKB fires. (Wait, I was so sure they were going to stop it like in ANH) The Resistance isn’t full of idiots, so they already abandoned the base. Except, now we get The Republic destruction. The Resistance Base target was a misdirect. The First Order has gone from non-existent to a bigger threat than the scattered Imperials now to the imposing force of the galaxy again. Big dynamic change from the opening crawl. Also sets up the underdog again.
The incomplete detonation wasn’t enough to stop the SKB fire, but it did do enough damage that SKB’s firing achieves its goal of destroying much of the Republic, but also creates serious problems. The base puts out an evac signal. Damaged but still being bad ass, Kylo Ren abandons the capture attempt of Rey, Finn, Chewie. It is clear that SKB will take major repair to fire again.
All the more reason to not waste time and find Luke …. End as the movie did.