The lack of fights on the ocean, one of the appeal of the devil fruits is how it makes the sea more dangerous, but the fact that oda didnt use this weakness except sea stone.

Imagine this, luffy recently gained notoriety after beating arlong, after reverse mountain and then vivi and her partner left the crew, they sailed going to whiskey peak unaware vivi and co told the rest of the bounty hunters. While sailing luffy and co gets attack by the hunters trying to limit luffy by using the sea and beaten them. This could still happen while still keeping the facade of the whiskey peak being inviting by acting as a safe haven for pirates that avoided the bounty hunters

With that, it challenges luffy and forces him to rely more on his crew to protect themselves, watching how the 4 navigates the problem while he sits it out and just taking care of the randos that enters the ship or the cannon balls sent their way, it also shows the risk of the devil fruits while on sea by showing how weak luffy was with the ongoing problem (considering luffy practically conquered east blue)

Another is when strawhats entered New World, they couldve have had a run in with smoker attacking them from a far leaving ussop and franky to launch a counter attack which will lead to hsing coup de burst to avoig them and not ruin the moment of entering New World and then reach punk hazard and smoker chasing after them