CoO and CoC are fine as they are, but CoA is replaced by kairouseki technology/accessories/weapons. A lot more devil fruit users are defeated using clever ways to drown them in the sea (which can also lead to fun things, like Luffy could have gotten a fishmen island device that insta-forms a bubble around him so… you think he got thrown in the sea and he's done for, but he emerges with the bubble! This would be similar to the vibe of Usopp's impact dial in Thriller Bark).
Oda's basic premise was made of devil fruits, countered by not being able to swim and then seastone, but these things played no major role in any fight whatsoever. Hell, Wano has seastone nails and nobody has used them so far in the main war.
One more problem which is very similar to this: early One Piece had log poses and eternal poses established as navigation mechanics. Then Oda introduced vivre cards (and he did that back in Alabasta, unless it was a clever retcon!). Now, I really love vivre cards because they are not eternal: you can get to the super secret island of secrets and make a vivre card of a local resident, but as soon as that person dies you're back at square one, which is a really clever plot device to make the Grand Line stay mysterious. It's much better than Eternal poses (which basically requires all major powers to keep a stash of those - before vivre cards were introduced I was always puzzled by, for instance, Smoker asking the navy to deliver him an eternal pose to Alabasta after Little Garden - how were they going to find him?).
However, I am really angry about vivre cards pointing to one another and not to the original user, as established by Rayleigh right before the timeskip. I do not understand why Oda chose to do this at all (I also do not understand why Ace's vivre card pointed to Ace himself, did he swallow the biggest piece?). So the way I would write it is: no eternal poses, vivre cards all around, vivre cards always point to the person they have been created from.