Oda is mature and cultured enough to not give a shit about teenage bullshit like "hype tool" and "power scaling".
He obviously loves Sanji just for the fact he's one of his most fleshed out characters. Like any, and I mean any decent writer will tell you that you don't create something like chapter 902 without connecting with your character; whenever you dislike a character (and I mean as a creation, not as a despicable individual) you have a hard time writing it yet Sanji's plots, whether you personally like them or not, whether they're better or worse executed, wouldn't exist if Oda hated him.
He obviously loves Sanji just for the fact he's one of his most fleshed out characters. Like any, and I mean any decent writer will tell you that you don't create something like chapter 902 without connecting with your character; whenever you dislike a character (and I mean as a creation, not as a despicable individual) you have a hard time writing it yet Sanji's plots, whether you personally like them or not, whether they're better or worse executed, wouldn't exist if Oda hated him.