This game has a lot right going for it, and if you have a Switch, then you can get the demo right now. I thought it was a great presentation, and I look forwards to seeing where this game goes. I know it seems like a small thing, but the HD rumble helps the game utilize feedback in a better way than any RPG has ever done before. Pretty much anything else I can say about it is said in the video above so I want to focus on the battle system; which I think is just about universally praised, but I have some issues with it.
First of all, I think a lot of people will like it. I have issues with it stemming from playing similar battle systems for extended periods of time in the Bravely Default franchise. In many cases, giving the players a little bit more to do in the interface works, but in a game that is heavy on battles this can get old and repetitive: Vagrant Story is an extreme example, but at the same time it's a shorter game, so the exhaustion with the battle system doesn't have the time to set in. The Bravely games gave the ability to use auto-battle and speed up mechanics, which really helped as well - unfortunately, this game lacks those sorts of features (so far); and in all honesty, if a game is going to go beyond the 15-20 hour mark, a more simplistic battle system tends to carry a game a lot further - not because it is more interesting, but because it is less of a hassle.
It didn't take long to figure out that the battle system essentially revolved around 1 thing - breaking enemies. Each enemy has a certain amount of shields, hitting them once with a weapon they are weak against will reduce that shield by 1, and when the shields run out, they break. This is when you hit them with your strongest attack for big damage. It's an interesting concept for a shorter game under 20 hours, but I can't see this system staying interesting for a 35-60 hour game, which is where I think this one will fall (based on developer history). It may be that battles will be far less prevalent than they were in the demo; but I doubt it, given Bravely Default.