Looks like it. The added content alone makes sure of that.
That they could port the game while still having it look good isn't surprising because the PS4 version wasn't all that special, contrary to the claims that Switch is allegedly not capable of handling the game and will get an HD port of the 3DS version. The scale of the game cannot compete with Xenoblade Chronicles 2; the playable sections are quite narrow and grand scope is only suggested with the land that lies below. Draw-in of foliage happens in immediate proximity at times, so it's not as smooth as XC2 in that regard.
I think the demo is that long because the game is slow to get started. It's only by the end of the demo that you get to play with a third and eventually fourth party member and that's already about seven hours into the game. On one hand it's generous that the demo is so long, but on the other hand Square-Enix would have done the game a disservice by cutting it shorter, because then players would have got to play only a very limited portion of the battle gameplay.