I say this as a fan of Frank Herbert, and I've read all the Dune books:
Thank god the Dune 3 movie looks like it isn't a strict adaptation of "Children of Dune".
Isn't it Dune Messiah? The book is terrible and I've never managed to make it through a second time. Children and especially God Emperor I enjoyed quite a lot, though.
You're not implying that the two firsts were strict adaptations in any way or shape, are you?
I read the main trilogy many years back; why would a faithful adaptation be a problem?