What do the Amazons have to do with Aokiji and Crocodile? Yes, Luffy was determined against Aokiji and Crocodile. It turns out that you need to be strong and determined, because Aokiji is strong. I don't see how this contradicts what I said. In fact, it seems to indicate that determination alone is not strength. Luffy would have done anything within his power to save the crew from Kuma, for example, but he couldn't do anything. He was too weak.
Luffy has used Haki maybe once or twice thus far, and did so without knowing what it is. The Amazons apparently use it for all their attacks. Therefore, the Amazons are better at using Haki than Luffy at this moment. Are generic amazons, who use Haki in all of their attacks, stronger and more determined than Luffy? No, they aren't. Infact, on the grand order of things, I'd say that alot of these Amazons we have seen aren't even that strong. The Strongest Amazons are with Boa Hancock, and the weaker ones are left on the island. Therefore, Haki isn't literally people who are "strong and determined" having special abilities (such as knocking people out, splitting the sky, or damaging Logia users).

Haki is the "chi" or "chakra" or whatever in One Piece. This is an established fact now.