In regards to Xenoblade 2's ending, I think Luminozero from GameFAQs said it best (source:
https://gamefaqs.gamespot.com/boards/204208-xenoblade-chronicles-2/76149799?page=1):
The ending sucks ass.
Let's put it all in context here, shall we? At it's core, Xenoblade Chronicles 2 is about Rex. It's a coming of age story, telling the story of an idealistic boy growing up and becoming a man. This is the story the game attempts to tell, using the world saving plot as a framing device, as most RPGs do.
That's the key thing you have to remember. The game is
heavily protagonist focused. It's about Rex.
When we first meet Rex, he's often mocked for being too idealistic and naive. It isn't until we meet Vandham that somebody begins to actually 'teach' him after displaying how Rex's weaknesses put others at risk. He breaks down Rex's idealistic view of war (pointing out that everything he salvages has military applications and that war is all about power, not morality) and acts as the 'experienced mentor' archetype to Rex's 'Young Hero'. It's the culmination of Vandham's character arc that, even with his death, Rex is incapable of making the adult decision and charges a vastly superior foe in a childish rage. Mythra later calls Rex out for this, making the player aware that Rex's refusal to accept difficult decisions is putting himself and all of his friends in danger.
Remember that line, it shows up again.
The game continues to progress, with Rex taking more of a classic RPG Hero role until near the end of Chapter 6. Once again, pushed into a corner, he recklessly engages a far superior foe and causes his companions to suffer for his foolishness. This time, Jin calls him out on it, noting how his foolishness has nearly killed Pyra due to their shared injuries. Once again, Rex's refusal to find another way out of the situation is what put them into the dire straights they wind up in at the end. Sure, Rex lacked the power to defeat Jin, but he didn't even consider a solution besides blitzing him and hoping for the best.
Chapter 7 starts with the humiliation conga for Rex, as his allies line up to slap the s*** out of him. The purpose of this isn't to just wail on the poor guy, but to call attention to something else entirely. Rex failed. Not only failed, Rex
acknowledged that he failed. For an idealist, acknowledging that somethings there is just nothing you can do can be world s***tering. His companions rightfully wanted to make him see that failure doesn't mean surrender, as many of the games antagonists took it to mean in their own backstories.
Rex's reaching out to Pyra and Mythra at the end of Chapter 7, oddly, doesn't indicate a large amount of character growth. The next bit really comes at the end of the game.
One thing that gets overlooked is a late game conversation with Zeke that has tremendous importance. Zeke asks Rex what he thinks about the world and the people in it. Rex responds with the affirmation that people "can be difficult to deal with. But you have to take the good with the bad."
This is an important part of Rex's character growth. The acknowledgment that there is bad in the world that has to be accepted along with all of the good. It's what he's never been able to do for the entire game, make a choice that isn't what he wants but is for the good of all. Rex just makes the choice he wants and hopes it all works out.
The next big event is Rex's "Nightmare" scenarios. The overarching theme here is that Rex failed to consider the feelings of his friends on the quest. He was so singularly focused on his goals (reaching Elysium, helping Pyra) that he didn't stop to consider their own. He's coming face-to-face with the fact that he's been extraordinarily selfish towards his companions for pretty much the entire game.
It culminates at the finale, when all of Rex's character growth is ready to be tested in a final, dramatic choice.
That is completely taken away from him.
When Pneuma destroys the bridge and makes Poppi promise to not help, she actively takes away Rex's
choice. What should have been his shining moment of character growth, to show that he really did grow up and learn that sometimes in life you do lose things you treasure, was snatched away from him in order to keep him 'pure'. Pneuma made the choice for him, robbing him of the growth and resolution to his character arc that such a choice would have represented.
There was still a lesson to be learned, though. That sometimes, despite our best efforts, we still suffer a great loss that shakes us to our very core. It's simply a natural part of being an adult, the world isn't as pure and fun as it was when we were a child. Rex had never accepted that before. He'd always believed there was
something he could do, and didn't stop until he found it. Except this time, there really was nothing, and all he could do was endure the pain as he lost her.
And then it was all restored minutes later, completely negating the sacrifice and torpedoing any chance of true character growth from Rex. Rex ends the game in the exact same "Youthful idealist" mindset that he started it.
For a game that intended from the very start to tell a "Coming of Age" narrative they failed
spectacularly because they didn't have the stones to stick with it until the end.
