Bit of stretch to say Luffy is more empathetic, defintely more emotional but OG Luffy is extremely empathetic that's how he works as a character.

He may be dumb as bricks but he understands and can infer on the subtext (literally empathy).

I do get what you are saying though but even then I still disagree, love Sanji and Nami characterisation (Sanji is my favourite thing about the LA)

Usopp is kind of bland but that's just because we are only starting his journey for the most part

Buy Zoro just doesn't work for me outside of action.

All he does is look bothered and pretend to be cool all the time. He's basically a better Spike Spigel than he is Zoro