Most fans don't like Skypiea beacuse it was disconnected from the current world situations and was consired a filler arc. But comon, why do they want Oda to finish up the story so bad?
1. Dials, need for Kabuto and upgrade the Clima Tact. Usopp uses the dials while figthing Luffy. If Skypiea is filler then why does Usopp have them?
2. Waver: found in the wharcked St. Briss ship, had not been for Skypiea it would be dial-less and beat up. Nami uses it after returning from Skypiea. If not for Skypiea then where does the White Horse 3 come from? Franky won't be upgrading it and it would not be in Thousand Sunny slot 3.
3. Gold: This plays an important part in Water 7. Without it they would not have 300 million berries and Franky would not be able to buy the Adam Wood to build Thousand Sunny
4. Klabutterman: This guy made it's frist appearance in Skypiea. He played a small role at the end of Enies Lobby
5. Phoneglyph: Gold Roger was here and it hinted the frist appearance of void century which is made clear in the Ohara flashback.
Skypiea was metioned at the beginning of Thriller Bark
Also Oda was going to finish of Going Merry in this arc but the arc went too long and Oda could not find a way to end Going Merry so he had to held it off until the end of Enies Lobby
Skypiea was unpopular among fans because how long and dragged it was. Such as:
Chopper being turned into a wimp
Norland subplot which makes you go "okay, we got it, we got it!"
Fighting the Natives who are good guys which was pointless
Waiper being annoying
Luffy Vs. Eneru was too dragged. just like the Oz battle.
Well, I like Skypiea however I wished Oda made it more deep with the Angel Island culture.