Reasons why oda stands above other manga authors..! no disrespect to ne other mangas...(heck i like bleach, naruto, fairy taiil mah self...)
1) 1 of all a point which i have noticed since a while, in his mangas oda never goes specifically into a certain part. he keeps moving the stry, does not get fixated on 1 thing for a long time...lik for eg in this war, we saw hancock kicks the pacifista head, or we saw hawkeyes vs vista, he does not go deeper into these needless fights, he leaves it for the anime to fill it up. Thats why if u notice, one piece has the least fillers, because every chapter can be filled up in 20 min anime because it gives them room to fill up the un-important parts skipped by the manga.
2) Character growth: In one piece when a person is said to be strong, he is bloody strong (well except for smoker who is under-rated in the manga, should be atleast titled v.a, while moria has been overestimated), like whitebeard, strongest man in the world, till now he has shown his strength, heck he was able to go up against an admiral with a stabbed wound and old age. the comanders of 1 n 3 division, have shown to be strong, marco was evenly matched with kizaru bt he gt distracted n tht led to his downfall which is very realistic. same with jjoz. iva right hand man/woman of dragon was able to go up against kuma. Luffy is strng bt not strng enough to be in their league.
3) keeps the story moving, every chapter brings something new or is leading to a build up. Oda loves to leave clues. for eg: squad o in 1 chapter was said to have vanished and also there was no sign of akainu, and then later we saw what happened. We have seen that the whole war arc has never been 1 sided, it keeps shifting which keeps us guessing what the hell will happen next. the war arc has been goin on since 20 chapters n we have seen how much it has progressed, while in bleach it takes ichigo 7 chapters to cross a 2 min path which gets so fustrating.
4) n finally the most imp of all, its realistic, the haki based attacks, we 1 saw luffy use it wen he stopped that cow/bull of that sanji duplicate. then we saw it again in amazon lily n den finally in the war. so its not like he suddenly gt this major power, he has shown us that luffy has haki n den shown us how powerful it is.
most imp of all luffy is the main character of the manga, yet in the war they have emphasised more on whitebeard crew and the admirals. However he has played a imp part n at some parts was very imp but has nt been given so much emphasis (like for eg kickin an admiral ass o somethin). He has been shown as being strong bt the level of a v.a tops.
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however one piece also has many faults like the new world pirates have not shown to be very strong besides the whitebeard crew n a few oder things..