They said they are using the same engine as the last two Divinity games plus an updrade. I highly doubt they are just going to scrap the whole turnbased side that has made them so famous over the last few years. If anything they will add stuff to the DM mode and maybe, just maybe create some kind of RTwP side. But Turn Based is definitely in as Wizards of the Coast hired them based on that sucess.
RTwP just failed a few years ago with Swords Coast Legends and no one batted an eye.