First image is from Episode 3 of One Piece where the FOX 4Kids dub edited the gun in Helmeppo's hand into some sort of bubble gun or some shit..
4KIDS (left) / ORIGINAL (right)
Next image is one of the more infamous edits 4Kids did not for violence, sexuality or reference to smoking or drinking. Did they do this to save from being labeled racist or did they do this because they are racist? Is it taking things to much into the realm of political correctness to change the characters skin color? In the following image there is a crew member of Buggy who is black in color in original, however the 4KIDS decide he should be white to protect the children..
These are just two early comparisons of changes there will be more in the future so stay tuned.
Another non physical edit to the show was the renaming of the Pirate Hunter Roronoa Zoro to Zolo. Since they were worried about conflicts with the name Zoro from the Mexican swordman with the mask and the Z slash. They are nothing alike except for having the same name and both using swords. Also Kuina Zoro's friend who he promised one of them would be the greatest swordsman is dead in the original but only sick and unable to continue being swordsman in the 4KIDS. 4KIDS tried to turn One Piece into a child friendly Americanized cartoon but that's not what it is and that's part of the reason it failed.
Also here is a link to the 4KIDS opening theme which has also garnered many harsh critics over the years. However I must admit when i first heard it i enjoyed it but upon watching the original i now know why people were so harsh on it.