Doesn't need to be a skill (never actually made sense to me in RS3 gold why it had been ). Make it a dungeon with drops and exceptional bosses which keeps shifting each time you go in. Have it give some currency for floors and supervisors to purchase rewards. Call it Delves or whatever and stick the entrance somewhere around the phenomenon being studied by it, that make sense with a base camp of NPCs. Make some lore that only instruments may affect the dungeon and some other reason for just food and also herbs in the dungeon work from the dungeon.
Progression can be unlocked by donating anything or some source found at the dungeon and boss kills to magic crystal or some NPC in the camp. Could probably tie this into or replace NMZ for this as it would make it simpler to explain why just stuff from the dungeon (dream delves) work and it keeps changing. Delve into the mind of a lunar wizard and we're just reliving it.
I'd love this. One of the content upgrades imo. So much fun if you had a routine 5 man and could fly through the floors in no time. Probably the most important thing I miss. Never really understood why so many people did not like it being a skill, most of the present skills are already very grindy, however in a lot of cases need little attention or ability, which is exactly what I enjoyed about dung - it actually had you engaged playing RuneScape, instead of being afk, zoned out grinding xp. It made use of your skills, therefore gave you motivation to level up everything but could nevertheless be appreciated at any level and didn't need any money. Your xp rate much satisfied in completing floors fast, so rewarded great teams. Was a layout for a skill imo.
It did not do rewards but they could easily be revived to match. Would have liked to see better execution of dungeons there were several resource dungeons but many were pretty forgettable. Could scrap all the weapons and armour imo (or make them temporary buffs for interior dung - eg buy an OP weapon that lasts x floors). Would really like to see things in it, possibly along the lines of Binding of Isaac, therefore theres an rng component you could struggle on some runs with. But once in a while the rng gods bless you with that golden run, together with the combos that are ideal and you decimate everything in cheap RS gold your path.