I've been thinking of ways to spice up pre-existing content so that players can have fun without the need for new content all the time. One way to help this issue is to improve the game's achievement system by adding something similar to World of Warcraft.

I am referring to the "Glory of" achievements. For those not familiar, these achievements reward titles, mounts, minions and other fluff for beating encounters under certain conditions. "Defeat X boss without any raid member getting hit by X mechanic," or "Defeat X boss in X amount of time." Usually, there is a meta that rewards for the completion of all achievements in the list, specific to a certain patch of raids or heroic dungeons.

Considering the wealth of content we already have, I feel this system could revitalize older content without it seeming like a grind, since it would add new facets to the fights. It would challenge those who like to test themselves, and reward them in a way that is visible to other players.