Penning some early Ghosts of Yōtei thoughts, going to try to keep it low spoilers. I'm not far in the game so there is some speculation on my end, but I'm confident of my assertions based on Tsushima and the reviews I've seen.
One core, crutchy trope of western narrative canon is that revenge is bad. Taking bloody revenge on someone or a group of someones for the violence they've done to you is almost always framed as self destructive and selfish, a poisoning of our innate state of innocence and purity.
Dozens of stories work to state this, justifying or rehabilitating the villains of a revenge story and making the audience feel for broken people caught in a cycle of violence that is out of their personal control. The revenge taker and the targets are pitiful, their actions a mistake.
Ghost of Yōtei, from all I understand of it, is another one of these tales. A woman wronged by a group of men, whose righteous crusade is shown to be a mistake and a waste. Her stakes are personal, her tragedy her own.
I am really, really sick of this story. And Yōtei had an opportunity to do something more interesting and palpable.
First off, I think that "revenge bad" is fine as far as penning your morality plays. There are lots of revenges that are bad. I do think that art that explores truly righteous revenge sticks so much more in my mind, and elevates it's stories by finding a truly worthy cause (Kill Bill and Darkman are excellent examples of this), but there are also stories of revenge as a destructive force that stick with me in the same way (Afro Samurai comes to mind most readily).
I think if you're going to make the argument that revenge is bad, especially right now when the world is overfull of people who deserve to have their hearts torn out in the marketplace, you really need to answer the question "why is it bad?".
Ghost of Yōtei takes place in the northernmost major island in the Japanese Archipelago, Hokkaido. The story is set against the earliest forms of colonial exploitation of the Hokkaido and the Ainu themselves. An early quest paints this picture quickly, where a bridge is being built by Clan Matsumae, the feudal family in charge of bringing Hokkaido into the fold. You're tasked by a samurai with defending the bridge from those that would burn it, leaving someone alive for questioning. A local overhears this and offers to help, suggesting that the local people weren't asked if they wanted a bridge there.
It turns out that the locals were paying ronin and mercenaries to burn the bridge, in the hope that the Matsumae would give up.
Indeed the local refugees from the recently ended civil wars (the Sengoku Jidai or Warring States Period) and aboriginal Ainu are trapped between Clan Matsumae's colonial project on behalf of the Tokugawa Shogunate, and the local warlord Seito, leader of the Yōtei Six. Seito is a man from a ruined samurai clan that fell during the civil war, who is calling the people of Hokkaido to join him in resisting the feudal control of the Matsumae. The Yōtei Six are the same that our protagonist Atsu has sworn vengeance against.
Do you see what I see here? We have a feudal house's colonial project, a group led by a warlord who seem hell-bent on using any and all methods to unify against southern influence, and a lady who really wants the leaders of that violent resistance dead.
When framed that way, Ghost of Yōtei's setup is compelling as hell! Atsu doesn't give a shit at the beginning of the story what happens to Yōtei as a whole. She captures and kills Seito's soldiers with impunity, and when she clears out a military fortification controlled by Seito, Clan Matsumae moves in to fill the vacuum. But as that early quest established, Clan Matsumae's rule wouldn't lead the people to prosper. What happens when Atsu's revenge tips the balance of power?
The main story in Ghost of Tsushima had similar problems with its storytelling; it had a very black and white view of the relationship between the rulers and the ruled, where samurai and their code of honor were good, the mongols were bad, and Jin's use of subterfuge to supplant the Mongols was unforgivable.
There is a version of Ghost of Yōtei whose second act is a realization of Atsu's complicity in an imperial project, and her efforts to—probably unsuccessfully—undo the mistakes made in her bloody revenge. That game's narrative has an answer to why revenge is bad!
It's just a shame that it's not the game we got.