What an excellent question, and it really helped me focus my Episode IX feels. I’d say the Battle of Endor from RotJ was the biggest with
significant resources thrown in on both sides with a ground battle
element, though the Battles of Scarif and Yavin were IMO better written
with higher emotional stakes.
My Episode IX
could roll all those elements together and bring the trio of trilogies
full circle to… the Second Battle of Tatooine! The existence and plans
of the Galactic Union have been revealed, and while it has failed to
take Coruscant the worlds loyal to the Union have declared their
allegiance. The Republic is split in two and turning on itself, while
Mandalore faces an impossible dilemma: Must it fight its own stolen
children? See also my alternate Episodes VII (link) and VIII (link).
The action would be divided into three
parts: space battle over Tatooine, ground battle on Tatooine, and an
uprising plot with Finn turning the Union’s Crusaders. The newly reinstated
Chancellor Leia Organa together with Admiral Ackbar leads the Republic
forces to Tatooine and Geonosis space, where the Galactic Union had been
hiding a large part of its fleet and personnel now ready to deploy and
take Naboo, Takodana, Jakku, Hosnia and more.
Leia implores
Boba Fett for help, but the Mandalorians have their own problems. The
part of the Republic now loyal to the Union is continuing the assault
against the Mandalorians, tying them down. The Mandalorians are also
hesitant to fight the main body of the Galactic Union and the Crusaders
who were revealed to be Mandalorians stolen as children. Unable to count
on Mandalorian help Leia nevertheless continues to Tatooine, Lando’s
fleet from Bespin joining hers. Poe and Black Squadron have scouted the
area and report back that the Union fleet are close to deploying. Luke
has already been on his home planet a while, brokering a peace treaty
between the Republic and the various factions on Tatooine with the help
of C3PO (link).
Rey
is on a separate mission looking for Finn. Finn himself, imprisoned and
being reconditioned, tries desperately to hang onto his sense of
self. Rey senses his pain and resolve, and dives into a dangerous
defunct hyperspace route in search of him. She makes it through a
hyperspace storm that she barely steers the Falcon through before finding herself in a
regular hyperspace route alongside the Union flagship. They drop
into normal space and so does she, and is tractored on board. Taken
prisoner and facing Kylo Ren with the Knights of Ren arrayed around him,
she finds Finn–standing guard next to Kylo, staring straight ahead,
not seeming to hear her pleas. Ren offers her a place in the Union and
she refuses. Ren then orders Finn to fight Rey, and during the fight reveals to her that Finn’s father killed her parents.
Rey realizes he’s telling the truth and fights back in hate and rage
until she realizes she is falling to the Dark Side and, remembering her
love for Finn, throws down her saber.
Ren orders Finn to kill
Rey and he marches forward, seemingly about to strike her down before he
turns his attack on Phasma. He had been repeating a phrase
drilled into him, a Mandalorian motto that the Union had stolen and
twisted around, and held onto it while he was being reconditioned. Now,
with the revelation of his heritage by Ren, his memories rush back and
he remembers his fathers, his sense of belonging, Mandalore in whose
ways he had been brought up all along though in a way that was twisted to serve his kidnappers. He
rallies the Crusaders, reminding them that they are Mandalorians even
though they were stolen and bred as weapons. They are not weapons,
however, they are warriors. Some of the Crusaders rally to him, others
turn on them, and there is enough confusion for Finn and Rey to escape
with the freed Mandalorians and damage the flagship in the process.
Back
on Tatooine the Tatooine Alliance of Hutts, Jawas, Tuskens, and farmers attack
the Union ships and supplies, destroying a significant number of ships
before they can launch. Luke is in the thick of the fray, with C3PO
complaining about how disorderly everything is and also directing a droids for espionage and sabotage.
In the space above
Tatooine Leia and Lando’s fleet shoot down the Union fleet while Ackbar
blocks off the perimeter with mines and bombers. The Union fleet is still an
enormous force and are wearing down the Republic fleet. They need help
and have nowhere to expect it from.
On Mandalore, the warriors
are defending the home world from Union forces while a Union
dreadnought moves into position for bombardment from orbit, a move that
would wipe out all life on the surface. At that desperate hour more
Union ships emerge from hyperspace and it looks like all is lost–but
these are the free Mandalorian warriors led by Finn and they fall on the
Dreadnought, destroying it! Finn informs the Mandalorians by comm of
what happened. Watching this brave young man, Idrian Fett and Teros Kryze are
gripped by the strangest feeling of recognition while telling themselves
it can’t be. The Mandalorians together send the Union fleet into a
route.
The Mandalorians must now decide whether to stay and
protect their homeworld or go to Leia and the Republic’s aid. Finn
argues that they must save the Republic’s fleet. The Union’s entire
strategy consisted of sowing dissension between the Republic and the
Mandalorians, and it is only together that they can win the day. Idrian,
thinking of the long-ago tragedy his own anger caused, backs him up,
convincing the Mandalore.
Over Tatooine Lando personally shoots down a number of ships
at the head of the Bespin fleet. Leia crashes enemy starships together
using the Force. Ackbar’s defense never wavers, despite great
sacrifices. Droid-piloted ships crash into the enemy, leaving holes in
their lines. Poe and Black Squadron bring down a capital ship. If the Republic is to fall here, they will make every death
count to at least give a fighting chance to the rest of the galaxy.
That
is when new Union ships arrive, alongside Mandalorian ships! There is
confusion for a moment before they realize the Mandalorian cavalry is
here, and the day seems to be theirs.
Meanwhile, the Tatooine Alliance back on the surface of the planet discover among the captured Union equipment some kind of regulator that is connected to one of Tatooine’s suns. Luke is stunned when he realizes that, essentially, the suns of Tatooine have been turned into bombs. The Union must have been waiting for their enemies to gather in one place and one of the suns will engulf the entire system in twenty minutes, setting off the other in a chain reaction.
Luke warns Leia to get the fleet out of harm’s way while he attempts to evacuate the planet, but when none of the ships can jump into hyperspace they realize that the Union has blocked off hyperspace travel in the area.
Then Kylo Ren’s Union flagship bursts into normal space. Ren informs his mother by comm that this system is about to be destroyed and he will take her away, installing her as the political head of the new Union to rule the galaxy as she sees fit–as she deserves to, as their family deserves to after all it has done for the universe. Leia flat-out refuses, saying she won’t be a puppet front for a mass murdering regime. She urges her son to stop the bomb and Kylo is angry with her, berating her for her ingratitude when he has paid such a high price for her. He tries to tractor and drag her ship into hyperspace, but she orders thrusters reversed and holds fast.
Ren, now panicked at the thought of losing his mother as well as his father, leads a boarding party to her ship to extract her. When the hatch opens he is greeted by Finn and his Mandalorian warriors who jump into battle with Ren and his Knights.
Meanwhile Rey is on the Falcon, having hit on a plan with Luke over the comm to try and open a hyperspace route to divert the solar flare from the first sun before it hits Tatooine and reaches the other sun in the system. Luke, with no time to join her physically, goes into Force meditation on Tatooine.
Finn and Ren have a rematch and it looks like Finn is done for when Ren disarms him. But Finn takes Ren’s lightsaber to replace his own, wins the fight, then pulls a T’Challa and captures Ren before he can kill himself. Ren needs to face a tribunal–and worse, his mother–for his crimes.
Together Rey and Luke manage to open a route into hyperspace and Rey disappears into it ahead of the flare, trapping it in hyperspace. Back on Tatooine Luke disappears in the light of the binary sunset, too much of his essence poured into the Force. Finn and the others watch and wait for Rey to emerge into normal space and contact them, but she doesn’t.
The battle won, the captured Union database gives the freed Mandalorians information of their origins and Finn reunites in an emotional scene with Idrian and Teros. Leia, unsmiling, tells an arrested Ben that he is grounded for life. A memorial is held for those lost in battle, and Rey’s name is among them.
After a time skip Finn is proclaiming the creation of a new joint force between the Republic and Mandalore to keep peace in the Outer Rim and root out slavery. At that moment a ship jumps out of hyperspace, its hull red-hot and visibly falling apart, and a giant gout of flame follows in its wake. Finn recognizes the Falcon and tells Rey through the Force to eject, which she does just before the Falcon is consumed by the flames and blows up. Told you my version of Finn solves far too many problems by ejecting people into space Finn blasts into space to catch her and they bring her in, burned, frostbitten, and barely conscious but clinging to Finn as she tells him she followed him home, his light burns so bright.
When Rey comes to she is safe and in treatment. Her right hand was damaged and had to replaced with a mechanical prosthesis. She is, little by little, introduced to the new reality and we learn it through her. The Galactic Union is in disarray, and Republic and Mandalorian forces are hunting them throughout space. Leia is working to pull the Republic back together and bring the pro-Union leaders to justice. Hearings are beginning on Ben’s trial. Rey talks about her own ordeal, how she was lost in space and time and thought she was going to die, how she found Finn’s Force signature in the maeltrom and made her way out.
Hesitantly Finn introduces Rey to his fathers, and Rey hears from Idrian himself what happened. She learns that her mother is alive, though comatose, and goes to see her in the same hospital. When Rey stands over her mother’s bed she and Finn both feel Irena trying to wake up and reach out to her daughter, and they clasp hands to join their Force powers and bring Irena back. You see glimpses of Force ghosts around the bed, Qui-Gonn, Obi-Wan, Yoda, Anakin, and Luke, helping them. Irena opens her eyes and, without a moment’s hesitation, calls her daughter’s name. They hug, camera pans out, credits.