Maybe if Campbell was still alive in the 1990s, he would have been able to help Lucas with his scripts for the prequels?

We now know Lucas wasn’t really a good storyteller. He was just really great with visuals, but was surrounded by great storytellers. His first wife Marcia and people like Irvin Kershner and Campbell were the ones who were able to convince Lucas that the story mattered more than the visuals. They were noticeable absent in the prequel production.