I would like to see a new dungeon added to the top of Korins tower, The Hyperbolic Time Chamber.

Possibly 100K for an hour with a 50-60% Exp boost with a bunch of mobs in there and the Chamber closes for a certain period of time to prevent too much of an OP effect.
or...
a Spaceship type room like the one Goku used to travel to Namek during the Frieza saga.
every level of added "Gravity" should cost around 5-7K for every sets of 10+ of added gravity
the Exp boost should start from 10% to 200% depending on the amount of zeni added.It should also have a timer set on it like the Hyperbolic Time Chamber.

Well I don't think Hyperbolic Time Chamber works well as a full dungeon would be great place for certain events like Korin's Tower did for the master class quest. Now if Kami's Lookout was the dungeon and part of the map was the hyperbolic time chamber (Special boss or something) that would fit better and still have your time slotted entry.

But I do like the idea of roaming dungeons that have limited access. That makes everything that comes from their very rare allowing for higher drop rates just because your on a clock.

Also the enhanced gravity is a good bit because being overweight would be a massive negative as it isn't a debuff that can be removed so players have to contend with the negatives while battling monsters/bosses that are just as strong as they would be reguardless of gravity. This would could have some strange effects like people paying attention to weight of gear again.

I just said on top of Korin's tower because Kamis lookout is directly on top of Korins tower and used to be connected by the power pole

Sorry mis understood the comma that suggested the whole thing was inside the hyperbolic time chamber.