Dune Messiah is Herbert’s knee-jerk reaction to the reception of Dune (it’ll be interesting to see how far Villeneuve goes with this) and is handy jumping-off point for the director. With a bit of a time jump, Children of Dune is also a good place to bring someone else on-board. If the studios are smart they’ll get another visionary director in and perhaps keep Villeneuve around as a producer, so he gets to help pick his successor and keep the films on track.