Its a recurring problem in part 2.
On PH, we spend too much time with Kin'emon and Momo. Oda really tries to make us care about Brownbeard who terrorized innocent civilians protected by Whitebeard before the TS. In contrast, Smoker, Tashigi, and G-5 are really entertaining and get the least focus.
DR has loads of characters introduced that I can't remember and because of this we spent a whopping 102 chapters on that island. In contrast, the Crocodile saga covers 117 chapters and we get to visit Reverse Mountain, Whiskey Peak, Little Garden, Drum, and Alabasta against the Doflamingo saga with 148 with only PH and DR. It makes the NW look smaller in scale in comparison to Paradise.
WCI is more simple and straight forward but I really don't understand the inclusion of Pedro and Carrot who is essentially Chopper 2.0. Adding Robin would have made more sense and brought actual stake to the plot.