No, just realistic about people's reactions on this site. Which I get, I love Ivy too...but the fact she can be killed early on...people should set their expectations that she is not that important in the grand scheme of the story.
I think ivy is almost a story of her own. You can leave them out of the main story, but you'll also miss out on a lot of history of the world. I bet it will limit options in the future with some foreshadowed conflict.
Raiders are the same, but I think they play a lesser role in the history. But you can already see that the
overpass mission would go entirely differently without knowing the raiders.
I also think that if you just take the raider or mutant story arcs and make them stand alone stories, they'd be on par with many of the quality AVNs out there. They'd be high quality stories and as much content as many completed games (granted with less time in development).