Koei has this problem where they think that bigger always means better, and a lot of the time (with them, at least), it's really not. Making an open-ish world for you to run around in is neat but it also feels like it's entirely just padding; this is especially prevalent at the end of the game where you have to run through parts of the world again without the ability to fast travel just to get to the last few missions. Also you can't take shortcuts. Or go back to shop/heal/save or else you'd need to run all the way back.

character movesets doesn't feel like they're really all that balanced, and the fact that Carver can mow down even the final boss fairly quickly is the best example of this. But that's one way to get around how much damage the enemies seem to be able to absorb.

honestly, if you want to play either of them, go play the first Dragon Quest Heroes instead of this one. It doesn't have some of the characters and some enemies can be even more damage sponge-y in that game than in this one, but the story and writing feels much better (somehow, considering how repetitive it can be at times) and the lack of the open world makes it feel snappier and easier to actually get through

it kinda feels like Koei is conflicted between wanting to make musou games and being too embarrassed to make musou games, and this game, more than any they've done, feels like it has no real idea what it wants to be