Why call it "Dune" if it isn't Dune, though? Other than just piggybacking his own story off the name brand of someone else's.

Not just "a bit"...he completely rewrote both Chani and Jessica's characters. He basically reversed their roles, for no other reason than because he fundamentally misunderstood what Paul's Character was supposed to represent.

It had nothing to do with "adapting" the story to the screen...he literally doesn't understand Paul's character, or why Frank Herbert wrote the story the way he did. So, he changed the entire story to match that misunderstanding.

This version may look great...but he butchered the narrative Herbert was trying to achieve. He actually managed to make the David Lynch adaptation look more faithful, by comparison. That's pretty bad.