The 'Lighter' Side Of The Force
On the subject of lightsabers didn't Anakin Skywalker do everything to make sure his lightsaber was completely different to Obi wans lightsaber contrary to Jedi law that Jedi make similar lightsabers to honor their masters.
The Lightsaber was an extension of the Jedi who builds and wields it, it was a very personal thing and was typically the only personal possession a Jedi owned. Lightsabers were also used as a focusing device during meditation as Jedi would attune themselves to the crystals within, some Jedi would use their connection through the force to become one with their Lightsaber. As far as honouring their Master by mimicking their design that too would be an individualistic choice, but most likely it would have been a subconscious result of the bond of Master and Padawn.
In bringing up Legends, you disprove your Luke uses Qui-Gons crystal. In Shadows of the Empire, it states that Luke makes his own synthetic green crystal.