Hopes isn't really lighter and softer. The director said that they didn't want to invalidate the stories of Houses, so the three routes in Hopes aren't exactly the best case scenarios. Dimitri's mental stability doesn't shatter, sure, but that was a major part of his growth. In his route in Hopes, he becomes a warrior king rather than being given the title of savior king by the masses. Claude's route is the antithesis of how he grew in Verdant Wind and while Edelgard might seem nicer in this game, changes made to the scenario undermine the idea that she's after anything but conquest and her army is incredibly brutal as they kill everyone who doesn't bend the knee to her. Rhea is supposedly more supported in Japan than Edelgard, but two out of the three routes end with Rhea being dead. Byleth is also popular, but they got sidelined for the new MC and didn't get any sort of arc (unless the player isn't able to recruit them, then they become an antagonist who kills an ally). And all of these routes effectively end on cliff-hangers, never coming to a real conclusion.
In Japan, Claude's fans are pissed they gave him a villain route and turned him into Edelgard. Dimitri is the most popular lord because of his character arc, and him not losing allies but at the same time never becoming as good as he could have been is seen as an insult. They're upset how the game tries to shill Edelgard even more by making her softer, while Rhea got completely screwed over. They're angry because unlike most musou games, these routes are being treated as just as canonical. They're upset because Edelgard and Claude's imperialism isn't presented as bad, Chinese fans even saying someone on the writing team must be a sympathizer of the Japanese far-right. They're also calling out releasing this in light of the situation in Ukraine, especially since the same studio put the Advance Wars rerelease on indefinite hiatus because of it.
As for the liberties? The English version of Houses made Claude more jokey. In Japan, Rhea emotes and it's heartbreaking in Crimson Flower while in English, her VA was directed to always sound like she's just barely holding back snapping. Edelgard's voice sounds cuter in Japan, because her being the red emperor is supposed to be a huge shock. In English, Edelgard sounds a lot more matter of fact, with her cutesy moments feeling like the shock (or in essence, they reversed her gap moe). There were lines that were removed like Edelgard using an information campaign to control her people, or altered.