Insperation from another thread made me want the devs to consider adding a similar dungeon to Nyzul Isle from FFXI.
For people that didnt play FFXI here is the jist of it.
In Nyzul Isle you would have 30 mins to complete 5 floors a run of a 100 floor dungeon, on each floor you would have a random specific objective you got at the start of a floor.
The obectives could be to find a NM, a specific mob, switch lamps on at the same time or in the right order or kill all mobs. The timing for this could be very tight and one slip up could cause a failure. Every 20 floors you would fight a weakend version of an open world king HNM which would drop the dungeon gear.
A dungeon like this would be a long term goal to reach the top floor for the gear or weapons.
If they wanted they could make it so for example feet pieces drop from the 20th floor, legs from the 40th, hands from the 60th, body from the 80th and head from the 100th which would make people want to take the time to get to the highest floor.
Every 5 floors you could record your progress do if you complete floor 5 and leave you could re-enter at floor 6 and it carrys on like that.
This is also a dungeon that would benifit from a time limit like 30 mins so timing is tight and you have to work as a team to get through.
The objectives I mentioned are just what was in FFXI and they could be anything the devs wanted, but this would be a long term climb and could be content that lasts awhile for the whole climb.