I thought that too when I started the series. The lack of "cool" or even normal looking characters is probably why it isn't as popular as stuff like naruto in the west.
But you start getting used to, and even appreciating the weird & exaggerated designs of the series.
Ehh, thats a cherry picked scene
The early parts of the series was just inconsistent in general. but the idea that the female designs being exaggerated was a post-timeskip thing is just some bad recency bias.
Alvida for instance is one of the earliest female characters of the series.
and this is from alabasta, the 2nd "big" arc. (approx 70 episodes, which is only less than 10% of the series)
I don't want to get into that topic too much but Alvida I find especially interesting because I remember her original design and the explanation as to why she suddenly looks sexy. They even made that transformation part of an episode or two where Luffy didn't remember her because she looked completely different. Maybe Alvida is the character that exemplifies the point in time where they decided they would go with sexy for most of their female characters in the future and later they looked at Nami and thought they needed to update her design too because Nami was invented before that. Just speculation of course.
