After reading rumours about a potential romance between the dwarf Kili and a made elf character played by the actress from Lost, I started wondering. Peter Jackson took some liberties with the source material from Lord of the Rings and made some dubious changes, like elves at Helms deep, Faramir's detour to Osgliath or the army of the death at Pelenor's field. So how much could Peter Jackson have changed and completely ruin the story?
For example:
Replace Legolas role in the fellowship with Arwen
Turn Merry and Sam's character in female characters to create some kind of romance with them and Pippin and Frodo
Turn Boromir into a standard villain (who was already working for Sauron/Saruman)
Remove Celeborn and create some sexual tension between Galadriel and Gandalf
etc.
For example:
Replace Legolas role in the fellowship with Arwen
Turn Merry and Sam's character in female characters to create some kind of romance with them and Pippin and Frodo
Turn Boromir into a standard villain (who was already working for Sauron/Saruman)
Remove Celeborn and create some sexual tension between Galadriel and Gandalf
etc.