The middle to end was probably my favorite part as we move into the action and we finally get a major space battle since Episode 3. Intro-mid was kind of the typical thing that I expected with the back story, setting up the basics, etc. Nothing too far out of the ordinary there. Might have been better to start things off when Galen was still in the Empire to make things more interesting which could also help character development for some of the characters who appear.
I do believe quite a few characters there could easily be replaced. Most were kind of there aside from the initial three who were barely, if not even affected by their presence nor do you get any major sense of them. The Imperial pilot just kind of defected and the other two just followed.
Also I could sort of tell with the CGI faces, I think, but they're not on screen long enough to be that much of an issue. I do not mind the CGI and I do think for certain things it makes sense, particularly large battles and settings. People, I can live with, I enjoyed the Episode 3 CGI stuff enough as it is. Besides it was nice to see some guys like Gold and Red Leader making brief appearance that shows they were involved in major Alliance operations.
Stop making Stormtroopers and normal grunts suck and giving the heroes a ton of plot armour against incoming-fire.
I don't care if you want to make your character badass, but do it where it actually makes sense. So many movies are notorious for this where it seems only gunning down a dozen enemies is a way to make people seem cool. Why not allow the heroes to play it smart? Why not allow them to avoid a fight or let them have actual skills that can bypass a fight all together? Some may find this boring but I'm a firm believer not everything should be done by 'kill more, kill harder' it should be 'kill less, kill smarter' sort of the idea. And this makes particular sense for the Rebels. They cannot afford fights unless they absolutely have to and what they are facing is an opposition who has better equipment, better training, greater numbers, and pretty much anything else you can think of.
You want an actual sense of urgency and that the heroes are in trouble when the bad guys are on them with their mooks? Let someone actually take a semi-fatal/crippling wound. Make it so that not every shot the heroes fire hits to show even our heroes do not have super cold nerves of steel or Mary-Sue accuracy. Make the opposition play it smart and do a variety of interesting things and less 'shoot until dead' or 'charge enemy despite having guns'. The heroes also do not need to clear every room of baddies as if they were in an arena. They're Rebels, they can afford to run away and hide.
Far too many Stormtroopers get gunned down or beat up in the most stupid instances that makes Endor less of a slaughter fest. These are supposed to be the Empire's primary troops who excel at quelling resistance, putting down rebellions and being a nightmare for the Rebels when the shooting start. The Tantive IV scene should be the standard for how Stormtroopers perform, even vs the heroes. You might get a few of them, but if you try to slog it out, you'll get massacred terribly. Heck, make each one near on standard with the Director's personal guard (at least when they shooting at people with no plot armour) to show the Rebels truly are fighting an uphill battle. Let there be a TR-8R in every trooper.
And can we please make the armour work for once? Heck make it so the armour is the reason one of our heroes gets hurt, etc. Shot is absorbed but the trooper keeps fighting and our hero gets shot.
TIE Fighter pilots are the exact opposite, however. Whenever you go into the cockpit of one, a Rebel pilot is probably going to die. Weird considering TIEs are supposed to be the expendable fighter to ever exist (aside from droid stuff), but they do pretty dang well for a flimsy fighters. Definitely should sign-up for the Imperial Navy as a pilot.
There's so much more of the universe that I wanted to see and now what happened to the galaxy afterwards that could have easily been incorporated. Change the Jakku to a major New Republic outpost/base with a sprawling landscape akin to the unique environments of the prequels that is responsible for trying to locate Luke. Maybe bring up the reason is to figure out why the Jedi fell once again like their predecessors, or even take him into custody for Kylo Ren and what happened. Then bring up the reason why the New Republic won't mobilize for war against the First Order immediately and have Leia appear earlier trying to argue for that support in the Senate before going off on her own; that would make much more sense why the Resistance has so little compared to the Rebel Alliance, despite the former actually being part of a larger apparatus. If anything the New Republic should be eager to go off to war considering they dealt with the Empire and they don't want that crap in their house again. By making themselves look weak during the Naboo Incident and the Clone Wars, they lost everything so they don't want to repeat the same mistakes.
Change Star Killer base from superweapon#1033 thing to something interesting such a sort of giant assembly area/meeting with the First Order negotiating or trying to gain support from what remains of the former Empire then have the good guys crash their party. Can still keep the same premise, but no stupid weakpoints, but instead just total destruction to ruin the First Order's get together with their grumpier cousins. Bring in the rest of the New Republic at this point to then show and even be the triggers for something far greater in terms of conflict between the factions.
And bam, you can keep the basic things including story development for the characters while making it more interesting without being a total rehash.