I've never seen anything of Dekker's, but honestly, writing is something that there's just no way to pre-judge based on past works. Eric Heisserer wrote the Nightmare On Elm Street remake, the The Thing reboot, Final Destination 5 and then... Arrival. I mean, damn.
And one way or another Black is co-writer and the actual director. He's easily the best director that has helmed a Predator movie since McTiernan, so I'm excited for him.