Perhaps this aura could be something that can be unlocked..maybe by unlocking all skills, or completing all missions, it will allow you to have this aura.
It would be something for the PvE crowd to show off, just like the PvP guys have rank...we could have an aura associated with our class.
It would be so cool to run around with my glowing green ranger...to say "hey look at me"

/Sign, because you know it's good.
