Dune is one of my favorite book series, I've read every one, even the ones Brian Herbert did based off of outlines his Dad wrote, and the prequels with Duke Leto and Paul set before the first trilogy
The only ones I didn't care for were the ones set during the The Butlerian Jihad. I couldn't get through even the first of those books, but the rest of the series is great, although the original 3 (Dune, Dune Messiah and Children of Dune) will always be my favorites.
But wouldn't you agree Dune is full of "future spoilers"? I mean, in the first book alone they outright tell you throughout Paul is the messiah who goes on to overthrow the emperor.