Honestly I don't mind the way Oda portrays women at all.
Personality wise his female characters seem to be strong willed and intelligent and, while they do have sex appeal, it's not like they constantly use their breasts to get what they want :/
As for his style I don't mind it in the slightest. It's a shonen manga so fan service is expected and even that isn't over the top. His proportions and stuff obviously aren't realistic but honestly who cares? It's his style. Their proportions aren't equal to that of women in real life but I REALLY don't look for that when I am reading a comic LOL How he draws women totally works for me, even with the newest chapters where Nami's breasts have upgraded. I really don't care, it's not like female character breast size distracts me from the story at all no matter how much cleavage they are showing.
tldr; I think Oda writes women with strong personalities and abilities and manages to make them sexy without writing them off as one dimensional sex objects.