I think both Luffy and Sanji reflects parts of Oda
Sanji is definitely designed around Luffy in a different sense too.
They have too much in common and too many similarities for it to be coincidence.
Yeah that would make sense, different aspects of Oda split between 2 characters, maybe even 3 with Shanks at most?
Aye, it really stood out at WCI especially, that scene of Luffy going to Sanji all starving, beaten and exhausted and saying he can't be pirate king without Sanji was one of the most powerfully beautiful things I've ever seen. Oda put his entire heart into it, like Luffy does with his actions and Sanji does with his cooking and what they both fight for/defend too.
Oda does have that really random whimsical nature that Luffy has too, that monkey cheeky playfulness too.