I don't know how much work this would make but I had an idea about how to implement more customization options along with rewarding both veteran and new players. Certain options could be unlocked based on your past triumphs (not your score). For example someone could unlock a particular scar by having completed the Vault of Glass in D1 or by going flawless. Major achievements could be rewarded this way and feel somewhat rewarding. I would say probably completing the big campaigns, raids and like reaching a certain number of kills in crucible/ flawless/ legend/ resetting ranks in crucible. That way it rewards both veteran player and new players could earn it with time. It reaches out to both PvE and PvP. Like I said adding Scars (or battle damage to exos) would be cool. New markings perhaps.