We've all made our guardians just how we want them; they're the class we want them, the race we want them, and they have the face we want them to have. It'd be a subtle, yet great customisation option if we could name them. It shouldn't show as a display name though, it should only be visible to others when they inspect your character. EDIT: to support and sign the petition, leave a comment saying: "Name our Guardians"
Create a new PSN or XBL. Say I wanted to name my guardian my current bungie username. Oh wait what's this I can't? Crap someone already took the name now I have I use more numbers or a completely different name. There's a reason for the current set up. Deal with it.