I do agree with the points you made, and I've used point #1 several times myself while debating the sexism in the Arlong Arc. Nami, Robin, and yes, even Vivi display a great amount of courage, determination, and perserverance under unimaginably difficult circumstances, which is a large part of the reason why I love them.

However, that isn't to say that I don't find other aspects of OP sexist, because unfortunately, I do. It's nothing that isn't in nearly every other form of entertainment out there, and it sure doesn't keep me from enjoying OP, but it is in there.