I would love to see this cave on Chronicals. I used to level up here on my old Euro Tao, got to level 42 in here. There were alto of bug exploits that people did use but there are ways around it, i feel the best ones to make the cave enjoyable and keeping it similar in ways might be,
New map, keep the mobs teleing to you and keeping the mobs that were previously used, but also adding your own for around the outter circle of where the old Euro mobs were. 2 Hour tele time to accommodate the new size map, and using variables on the groups that enter to make sure you still have 2 of each class in the group if not it will tele you out of there. Also placing the final check to enter the cave at the very last click not at the start as it was on Euro and USA Mir.
The downfall to two of my suggestions is if someone has to leave the group for personal reasons (usually kids) then the group thats left will be teled out, also if a player dies it would need to be made so that they leave the group rather than stay in and revive in the town as the variables will still class this as there in the cave, but there again you could have it check the BG map for each players to see what map they are located on.
this would need to be confirmed by the npc developer to make sure this can be done or from coders as it might need adding.