No one uses honorifics in English either, so what would you have them do? You're not going to get an exact match for that sort of vocal affectation, so you're basically damned either way. Sure, it sounds awkward, but in a derpy lovestruck way that's generally in-character with that side of Sanji.
And on the contrary, I'd rank OP as an absolutely top-tier dub job, which is remarkable given the absurd number of episodes that have been pumped out by this point. The main cast is very comfortable with their roles and have aptly handled both the big dramatic scenes and the goofy comedy, at least in my experience. I mean yes, you're not going to beat out the likes of Mayumi Tanaka or Ikue Otani, but Colleen and Brina do a damn fine job in their own right.