They triggered the story because they were the first ones, it's lame trying to compare Sanji's importance with Nami's in the grand scheme of things, Usopp came first than Sanji and it's the same thing.
Baratie arc has Zoro fighting Mihawk, losing and stating his life time goal, it has Luffy having his first extreme diff fight and talking about never giving up on his goal, being saved by Sanji and both having particular moments. Sanji witnessed all of that with his own eyes, one of the reasons for him to set sail it's that Zeff saw on Luffy the same thing Sanji was hiding within himself
It's not hard to see that without Zoro and Sanji, the Strawhats would have died long ago, their decisions and actions make huge differences in the plot. Obviously without Nami's assistance they wouldn't even set sail properly or reach their goal, thats undeniable.
You guys get salty with the Zoro/Sanji wings thing but are fine with saying that Nami has more overall importance than Sanji.