Since you guys are reading and arguing based on this translation, you might want to know what the translator had to say about this at the end of the chapter, in the Chapter Notes :
Basically Robin is saying the exact same thing Oda did back in the SBS, and since she's refering to Sanji specifically, the translator called him "One of the Wings" to account for Zoro not being the focus of this particular piece of dialogue. Zoro is the other one.
Also, i honestly don't like the toxicity in the thread made to discuss this moment, with the very opening post starting with a premise that invites such toxicity by claiming that this is evidence for Sanji = Zoro in strength.
This does not prove that, let's be clear and honest with that.
Let's be clear with what it does prove as well though, and that's that Zoro and Sanji are exceptional within the crew and stand out above the rest
So no, it doesn't mean Sanji = Zoro. At least not when you narrow it down to just strength. Yes, it does mean that Zoro and Sanji > others.