That goes completely against what Oda said about her. Smoker and Tashigi will be MUCH stronger by the end of the series. If not, they have no right to chase Luffy throughout the whole series, and Tashigi's name explanation by Oda would be pointless.
+ means they are getting much stronger
Robin+, Bonney+, Big Mom, Tsuru, Tashigi+ (end game will be stronger than Tsuru), Smoothie, Carrot+, Koala+. Just to name a few females that Nami will never surpass in strength. And she isn't getting Zeus. It would mean that a cloud was always following her around, and it would be 99% of her strength. How bad would that be? I liked the theory that said this side of Big Mom showing in Zeus (how he became friends with them with food and praise) is a sign of things to come with the Luffy-Big Mom alliance/friendship.
Maybe Nami surpasses Hancock (not really growing in strength anymore), but I wouldn't call her one of the strongest if she isn't even top 5 (not even top 10 when we see the other strong females in the world). Nami's strength lies in her smarts and navigating, not in her ranking against others in strength. That's why she will always rank 2nd weakest in the crew, only in front of Ussop.
They can get stronger sure, but that won't actually make them popular though strength and popularity are not really the same thing