I think growth and development are separate things from a storytelling perspective. They seem similar, but there's actually a subtle difference that differentiates them.
So the thing about character development, is that it usually effects the core of the character completely, and usually (but not always) the character is changed because of it. There are very few instances of this for the Straw Hats outside of their individual arcs, in my opinion. I think another facet of character development is that it's usually brought on by circumstances, usually it's easy to point to actual things in the story that cause character development to happen, like Ace's death for Luffy. I'll use Zoro as an example. He gets real character development when he loses to Mihawk. At this point we hadn't seen him lose before, and not nearly that badly. He cries out to Luffy, the first and only time we see him crying, that he will become stronger. This is also the very first time he acknowledges Luffy as the Pirate King.
This is character development. Zoro internalizes his defeat by Mihawk, and gains resolve because of it. He's given a reality check by fighting the strongest in the world, and it causes him to grow. Noticeably, it's after this defeat when we get shots of Zoro training hardcore, lifting weights and stuff. Before this, we never really saw him train.
The difference is with character growth, that a character can grow, maybe even change slightly, but the difference is that there's no internalization happening.
I'll use Zoro again as an example. On Thriller Bark, we see him abandon his dream for the sake of Luffy's, and try to sacrifice himself for the rest of the crew. This seems like character development, but it's actually growth. You see nothing is really changed about Zoro's character, nothing is really internalized. After this is over, the SH's go back to being how they were before, but nothing has been changed or internalized for Zoro. He has grown as a character in our eyes, but he hasn't developed.
Not all growth is transformative, and leads to change. But character growth, in my opinion, is no less important or meaningful than development.
I think one of the coolest aspects of One Piece is how reactionary the Straw Hats are as protagonists. Most protagonists in story go through conflict, meet people, then are changed and developed by that conflict and those people. With the Straw Hats, it always seems to be reversed. It's the people they meet because of the situations they get into that end up being the ones who change. This is primarily how Luffy gets people to join the crew in the first place, and it's extremely satisfying when that happens. Almost every arc we see minor characters change due to the influence of the Straw Hats. This reversal of development that the SH's have as a crew is why the new Straw Hat members get insane amounts of character development in their own arcs, and then after that don't really change, but grow.
Awesome post . I managed to learn few new things from this .