That’s not true, it was important. Just as Chopper’s was. She was not the main factor, as again, Pekoms was the one that convinced Luffy. She told him the entire story and he was still unsure about what it meant. Nami being more important does, because if she has the spotlight then others don’t. She is more important, thus more highlighted. This is the same for Zoro. As a matter of fact, this is why Zoro was more prominent among the Dressrosa group. It’s the exact same thing. She wasn’t the most troubled by it, either. They were all troubled, and then Luffy found out exactly what was going to happen from Pekoms, and then he was the most. She was absolutely concerned, but not more than anyone else.