Oda said that Nami was core of One Piece 20 years ago.
In that same time Sanjino was supposed to be near to Zoro in strenght, but that was debunked Post-Time Skip. What's the relevance of Nami right now? Sanjino got his arc, Zoro is getting his now and Ussop will probably have Elbaf. Imo, the arc where Nami got more shine was in WHC...
If Oda really want me to believe Nami is that important he at least needs to turn her in an Ancient Weapon. I really like her and Arlong Park was a pretty good character development, but after TS she was left aside.
Also, now we have Jinbe to outshine her in the ship travels