It looks like a Musou / Warriors game, but in some ways it doesn't, and the word doesn't get used in the trailer. TheGreatNads speculates that it could be something along the lines of Trinity: Souls of Zill O'll, which uses the Musou engine for a different kind of action RPG experience, and I think an "engine spinoff" is likely as well.
A couple things interest me about this, beyond the obvious opportunity to play a Dragon Quest game from Omega Force. One is Square Enix and Koei working together. It's too bad they didn't hook up earlier, because Omega Force could have made those atrocious Dissidia games into something worth playing. Two is Dragon Quest coming back to Sony (on consoles, no less!)—I'd love to see Dragon Warrior VII get a PSOne Classics release, or an HD remaster of Dragon Quest VIII. Obviously, a proper non-MMO next-gen entry in the main series would be incredible. Three is this hilarious special edition PS4 that'll be released alongside the game:

Sweet "Metal Slime" edition. This is unlikely to leave Japan, though.
