Running around the Wilderness, made me wonder, what could be those rifts in there, just placed around 4 - 10 level Wilderness, north of Edgeville.
Seems like legit dungeon, brought from Rs3, called Chaos Tunnels. Now, some people figures, no thanks, a bit huge for dungeon and maybe dangerous to travel for those who avoid being PKed or unprepared to walk around inside it, just because of it's own messy design, in which anyone can be confused. My Idea, is implementing something like this, just a bit smaller, for monsters seen inside it. Not every NPCs and monsters in it, are found in-game, so I probably suggest, to cut it and make it somewhat enabled. Leaving unused ground textures, don't seem right. I do realize, it may take months or whole year for this to be released in game, but having more wider access to dungeons is one feature we could use. Oh, and in addition to this whole suggestion, it is members-only, expanding members features. Maybe, requirement would be nice, considering that place not making easy escape just for any player, and requiring 72 Agility to climb down the rift and 83 Slayer.
For last, Bork is the Boss of this dungeon. Adding him would be nice feature, though, not sure if needed, because, I haven't thought any good drops to book in his drop table, seeing him in Rs3. He gives Slayer Exp, so maybe, making him a task, that would give 5000 experience per kill, would be great.
For drops, I had in mind 1 in 500 starved ancient effigies, thing that implement assistance system between two players in specific list of skills.
Ancient effigies themselves, could brought a new diversion mini-game.