I would say tell your player to cram it with some legacy walnuts. Take the weapon, tell him to focus on the campaign on hand, and if he doesn't constantly pine after it, give it to him when it would be best for the plot.

There's nothing wrong with designing for your character to excel at what they do. Many of my characters have been reasonably optimal with their builds. However, I feel like some people would benefit from planning their character's development in a story sense. No matter how you slice it, "poof, got a magic weapon!" isn't very cohesive to story development.