I don't like neither Sanji nor Usopp getting CoC, but I can easily see any of them getting it.
On another note:
While Sanji said Zoro to throw away his ambition to save his life, for example.
4-Ussop wants to "lead" an army, he's definitely more like a Conqueror than Sanji.
First the bolded part: nothing against you or anything,
@Thururuzao, but I REALLY don't get this conclusion. There are plenty of characters across fiction with this theme of "not believing in themselves" at first. Sanji is not the first, and won't be the last to explore this kind of dilemma. So I really don't understand why people simply trap themselves to a side of the character that was dealt with ON THE SAME ARC HE WAS INTRODUCED.
The "Sanji that would tell Zoro to throw his dream away" died the moment he turned to Luffy and asked him "Hey, have you ever heard about the All Blue?".
Among the SH's, Sanji's dream of finding the All Blue is the most similar to Luffy's dream. Luffy wants to become the PK, and, for that, he needs to find the One Piece, a treasure that people believe to be a myth. Countless times Luffy was laughed at because of his dream. The same way Sanji wants to find some mystical sea that no one knows for sure if it evens exist.
They are like "Milo" from Atlantis, or Jim, from "treasure planet". Searching for some "fairy tail". The fact that Oda doesn't talk about the All Blue all that much during the story means very little. It will become relevant only when time calls for it to be relevant.
From "throw away your stupid dream" on Baratie to "what about your dream?" on Thriller Bark. Stop trapping your view on the character with just a piece of his story.
Second, about the "4th" point. Luffy does not want to lead an army. In fact, he actually "rejected" his Grand Fleet and just told them they would be friends and he would call for them if he needed help, just like he would help them if needed. Meanwhile Sanji ACTUALLY led people.
He turned Duval's gang into allies, he led the G-5 Marines in Punk Hazard. He turned Viola into an ally, he turned Pudding into an ally, etc.
Usopp had a great interaction with Dorry and Broggy, he turned the Ennies Lobby giants into allies, he led the Tontatta.
I think they both fit the "leading an army" point.