What does late game look like for this type of MMO?

You have hit max level after months or maybe even years of hard grinding. Your guild rallies together and you slay the big bad dragons and plunder their nests for loot. You have acquired the big shiny magical weapons and armor. Now what?

Late game has always been one of the more difficult parts to design for this type of MMO. Players spend years investing time into a character building up their stats and completing quests to acquire the coolest stuff and often the best part of getting said stuff is getting to show it off. I am curious what kind of late game systems this community is wanting for this game that will keep them logging in after they have killed all the end game bosses.

Or perhaps this game is not about the end game. Maybe like a DnD campaign once you kill the BBG that's the end of the experience and your character acts as a trophy of your accomplishments. Perhaps the journey of climbing the mountain is the meat of the game. Once you reach the top you climb back down and do it over again.