Wano is the climax of 400 chapters of the manga. Nothing wrong with the fights on for a while. If Oda couldn’t add that much more chapters, there’s several other stuff that could be cut. Udon could have easily been only half as long as it really was without making the story suffer. In fact, shortening Udon would have improved the pacing by a lot. Cut the Luffy and Kid rivalry filler since that gets done in Onigashima anyways, making it redundant. The Mummy stuff didn’t need to go on for like 2-3 chapters. Make it only one chapter. Shorten the Gifter fights and Queen’s goofiness. Don’t drag out the Kawamatsu reveal for so long with like a million silhouettes. He didn’t even end up being very important. Cut the Yakuza bosses. They are literal background characters. They haven’t done a damn thing in the entire story so far, and they most likely won’t do anything in the future. A lot of the Flower Capital filler could be shortened too. The Soba Mask plotline honestly shouldn’t have happened. Have Sanji use the RS for the first time against Queen. Sanji would be pushed into a corner by Queen, and Sanji will have to learn to swallow his pride and use the Raid Suit in order to save his nakama. Cut the Oniwabanshu. They were total trash and didn’t do anything. Keep Fukurokuju though, and make being a ninja look more prestigious since only him, Raizo, and Shinobu would be ninja. There’s also plenty of wasted panels on fodder Gifters in Onigashima.
Oda never does that. Marineford was the climax of the Ace storyline from Alabasta and was Built up as the biggest War at that time. Lasted 30 chapters entirely. One Piece has always been like this. People were complaining about Marineford, Enies Lobby, Dressrosa, WCI and every arc pretty much when it was coming out weekly. Japanese Manga are meant to be read by volumes, especially the war arcs. Re reading arcs in their entirety would be a much better reading and this is from experience.
The Mummy stuff was important because that Luffy speech was taken from Akiro Kurosawa's Seven Samurai, the story about which Wano is based on. If you remove all the filler, then Wano will feel super bland and people will again complain about the lack of Worldbuilding when compared to previous arcs or pre timeskip. And you know that the gifter fodder panels were for delaying Luffy going to rooftop till ch 1000 and to show how big Kaido's army is.
I think @Van pointed this out before, but I think one of Oda’s problems is that he gets too ambitious at the beginning of arcs and goes overboard with the worldbuilding, which causes him to cut some content in order to stay more in line with his original targeted arc length. Characters like the Yakuza, Mimawarigumi, and Oniwabanshu were a total waste of space and added nothing to the arc. Honestly, even some of the Scabbards didn’t need to be included. Ashura, Kawamatsu, and Kiku didn’t need to exist, and without Kiku, Izo wouldn’t really need to come into the arc. This would leave us with 5 Scabbards: the Dukes, Kinemon, Raizo, and Denjiro. This would add to Denjiro’s torment since he would know he’s the only one of Oden’s subordinates left on Wano for those 20 years. I like Ashura and am ok with Kiku and Kawa as characters, but they weren’t really needed. Less Scabbards means that the remaining Scabbards get more development, as well as the rest of the cast too
As I said Cut all the worldbuilding and the arc will feel more like a Davy Back fight but a war between the two crews. The Yakuza, Mimawarigumi and Oniwabanshu all existed in Edo Period Japan and Oda included them in his worldbuilding of Wano because they represent his culture and Japanese roots.
You cannot just straight up cut everything just for "fights". The Same criticisms can be told about Enies Lobby - like the entire World Building, Franky Family filler, the Aqua Laguna etc can be removed. I'm sure people were complaining about Buggy filler in Marineford arc instead of Whitebeard pirates vs Admirals fights just like how people complained about Tama filler in Wano.
As I said, if you wanted fights for 50+ chapters, you can read Baki or other fighting Manga.
I'm not saying Wano is flawless. The pacing of Act 2 was kinda iffy (felt fast at some instances and slow at others) while I personally wanted more characterisation / expansion on each scabbard's relationship with Oden. I will have more criticisms when I read Act 3 along with Act 1 & 2 together. But there is a reason why your version of Wano arc isn't the one being published on Shueisha while Oda has made enough money for multiple lifetimes.