Had this suggestion for a huge change to Avatar Fire and Ash that would have helped it in a lot of ways.
In the final act, watching the movie for the first time, I was really sure that Jake Sully was going to die. Seeing him give himself up to be captured, the fact that I went in hearing that this would feel like a "fauxnale" or the conclusion to the story threads Way of Water set up, even the slight full circle feeling I was getting, all of it made me think "Okay, Jake is probably going to die"
Personally speaking, I feel that this one single change would have had a lot of consequences.
- It would have been intriguing to have Quarich go more and more "native" and experience some of what Jake experienced that led to him choosing to live on Pandora full time, in the same film where Jake ends up having to die for the sake of Pandora. That one choice from Jake to sacrifice himself would have been the perfect way to take away Quarich's disdain and desire for revenge. He'd see Jake die a true solider, for the place he loves. Also, since he no longer has that personal desire for revenge, and given how he's being pulled away from the Military group that resurrected and hired him, this could have cemented his transition into a total Wild Card. Is he a villain still? We don't know at this point and that mystery creates more suspense for the next film.
I'd add to this by having him destroy Bridgehead in response to what Jake did, but if you don't want to go that far, just have a shot of him looking at Bridgehead, and then turning away to walk with the Fire Clan.
It would have been the perfect chance to reverse the eye opening from the first two films. Avatar 1 ends with Jake finally in his new Avatar body. Way of Water repeats this, but Jake just closes his eyes and then opens them, like he's going "I can't relax, there's a conflict ahead of us". Fire and Ash could have ended with an intercut sequence where Jake's body finally closes it's eyes. Think about it, he chose Pandora in the first film, he maintained his family in the second, and he died for his family/new home in the third.
It would have tied the first three films together as "The Jake Sully trilogy" and made it clear that these next two films would focus more on the younger generation growing up. One of the common coming of age story beats is the death/removal of the parent and I think it's a shock that Jake and Neytiri are still alive.
It would leave Neytiri in an interesting place. Jake was the ultimate proof that humans aren't all bad, but he's dead after spending all this time as the same species as her. And he died not just for the Navi, but for Spider who is a human. Jake also was a grounding figure, so what the hell happens when she doesn't have that in her life?
Worthington's acting is the best in trilogy in Fire and Ash, and it could have given him a powerful scene to go out on.
It would have fixed a lot of complaints regarding repetition. Not only would a lot of call-backs felt more warranted given how this was Jake's last hurrah, but it also would have ended by doing something that we've not seen yet in the sequels, the death of an important protagonist character. Way of Water and Fire and Ash end by killing off a side character, but not a lead. And killing off the perfect brother, followed by the gruff father, that would have been a nice throughline.
Fire and Ash wouldn't have still felt like it was stalling by the end if it did something as simple as take Jake off the board. Once you do that, you have progression even if the RDA are still standing.
The scene with Spider and Jake is pretty strong on it's own, but I think it would have been even stronger if Jake had died at the end. Jake is put in a position where he feels like he has to kill this extra son that he cares for, but he simply can't go through with it, and he ultimately proves just how much he cares by dying for his children, including Spider himself. Imagine that "With all of my heart!" exchange being repeated, but reversed. It would feel like validation, like Jake had provided that he cared for Spider more than Quarich, his own biological father.