Having other Deep Dungeons would be good to provide a change of backdrop. each one with a higher base level requirement to get into it with a higher focus on party composition and possible floor mechanics or enemy mechanics.

Could make a entry level 50 Deep Dungeon: A Realm Reborn Boss Rush (and a HW version) where on each floor you are facing off against copies of the dungeon/trial bosses. With the occasional storyline scenario boss (like Raubahn) making an appearance. Could be some Allagan Simulation Node that woke up with the crystal tower and had been scanning and cataloging all the events that have transpired and the people/beings involved.