I think PJ handled it well.. but I'm not bothered by Aragorn carrying it around as a Ranger in the book. The psychological attachment would be strong, especially now that he knows his time is coming. And when sneaking aound in the Wild, the knife, or bow would probably be more useful. Remember, Aragorn uses fire not swordplay (even in the film, I think) to fight off the Nazgul. A heavy sword would be a hindrance more than a help in the Wild, and was it not just the hilt and a small part of blade Aragorn carried? An emblem and reminder of who he really was? Narsil is reforged
in the book, but were 'shards' as such mentioned? Don't blades get made from molten metal? Do 'shards' get melded together? If so, they might have been left in Rivendell (to save them rattling in his bag in the bushes in the Wild).
In the book, Aragorn's sword was reforged before he left Rivendell, wasn't it? His time of slinking in the shadows was drawing to an end. He was going on one last 'sneak' to Gondor, but then War would be upon him!
(NB GB, it's not very nice to whisper behind people's backs!