I personally didn't get the chance to play neither the Gorge nor the Forge, but I have played with mods who make these events come back and I quite enjoyed playing, I really think the gorge and forge should make a comeback, maybe not as an limited event though.
Here are some ways I think the Gorge and the Forge could be implimented back into the game.
1. There could be a setting in the menu in the events settings, with the Winter's Feast, Hallowed Nights, ect.
2. There could be two brand new islands in the main world, they did impliment sailable oceans with "Return of Them", so this is possible. There could be ports, which would be the only place you could board on. Uppon exiting your boat, there could be a warning that says you might not be able to go back for a while, you would drop all your items would drop on your boat and would be locked inside until either success or failure. Once your in, it would be exactly the same as were the events. If you win, one, you can leave, two, you get some sort of reward, maybe a blueprint for the farm plots of the gorge, or for the forge, a blueprint for a new weapon. If you lose, you would simply wake up on your boat, with no consequence other then time loss.
There are other ways in which this could be implimented, but I really like my second suggestion.