The post time-skip stuff just suffers from a shit ton of shonen tropes that earlier stuff subverted a lot of. There's also next to no struggle against any enemies at any point, since the entire crew is super OP at this point.
I'd say the best of the show is from Arlong to Water 7, everything before and after that isn't as good.
Arlong is my favorite arc, when I rewatched the pre-Grandline stuff, I was really surprised by how much more I was enjoying it. (The pacing issues definitely mar the experience in the later arcs)
And yeah, I prefer when every fight is a struggle, but I hate the "Oh he died! lolnohedidn't" nonsense that really began go to overboard in Crocodile's arc. Even though I love Crocodile, Luffy 'died' like 3 times, and I actually raged when that bird guy came back. Why should I feel any tension when I know no one will actually get hurt in any meaningful way?
I felt so much more with
than anything else post-Arlong.
was spoiled to me, and the anime stretched it out between episodes so it removed alot of the impact.