Response to Max B.
Aaron B.

Max B. has overlooked a crucial aspect of the LOTR plot in his naive suggestion that Arwen replace Legolas in the Fellowship.

Perhaps this has already been mentioned, but having Arwen replace Legolas would significantly affect Aragorn's relationship with Eowyn and her unrequited love for him. It was Legolas, along with Gimli, who accompanied Aragorn to rescue Merry and Pippin from the Orcs in Rohan, meet Theoden and Eowyn at Edoras, fight at Helm's Deep, and brave the Paths of the Dead. Would Eowyn really have fallen for Aragorn in such a dramatic and open fashion if his betrothed, an elvish princess of unparalleled beauty, were with him? Would Eowyn have confessed her love for Aragorn and begged on her hands and knees to accompany Aragorn on the Paths of the Dead, with Arwen standing nearby?

Of course not. Clearly, altering the makeup of the Fellowship of the Ring and replacing Legolas with Arwen would substantially alter Tolkein's plot and the development of his characters, not withstanding Max B.'s wistful suggestion to the contrary.