Honestly, they should leave Peter Dinklage's voice acting in. Then have a mission where in a close encounter with Oryx, he strikes down dinklebot, and you just deliver its shattered remains to the traveler. He then reconstructs the ghost in its new form. You see his little light flicker, and then it goes from its bluish tint to a brighter white. You drop ghost to the ground and look away, a sadness in our guardians eyes, then we hear Nolan's voice for the first time. "Eyes up Guardian," he says, the voice different, yet the experience familiar. Pasting another voice over his part is just cruddy of Bungie. It kind of negates the relationship between year one players and their ghost.