I believe it turned out he was the mission designer for the Bloody Baron quest, rather than the writer. Still, they have good writers on board and I'm confident this will be a shit load better than the dire writing of Killzone (and I say that as a fan of the series).
I think good mission structure is important too. A mission can be as well written as you want but when it consists of just running someplace and grabbing something and returning to the sender then all the writing in the world won't help you. Well maybe if you're poking fun at the very thing like the mission to rescue "Princess" in the Witcher 3.