Yes by the end of the book he has been through several life changing experiences. Also significant I think is Galadriel's warning. By the end of the books Legolas is fundamentally changed in his attitude to Middle Earth. He has heard the song of the sea and now, even in the depths of Fangorn or his new Princedom of Ithilien he knows that he will not stay. His heart is partly over the sea which connects him to a whole other branch of elvenkind and elven history. For me this feels like a maturing process, a rite of passage in a way. Adolescents famously tend not to acknowledge their own mortality, to grasp the realities of life threatening dangers. Part of the transition into adulthood is meeting the fact of one's own mortality, one's own death. Legolas's passing will be a more literal one but will still sunder him forever from Middle Earth and that awareness will - always - be - with - him!