Unlike in Lone Story which is a straight rush, in Duviri Experience people usually like to split up across the plain to explore and immerse the environments, gather resources/decree and find fragments, feed the maws, and solve Enigma puzzles, same as the other Openworld plains, for almost an hour before finishing the Orowyrm, or even leave after getting enough resources without taking on the Orowyrm at all.
And to have Undercroft force dragging everyone in when someone enters (unlike in the three other plains where everyone can vote to start or cancel the bounty when someone carelessly accepts one in blaze) and leave them at the entrance far away from where they were after it's done is interrupting and sometimes progress breaking especially when trying to solve Enigma puzzles or trying to find the fragment they heard or marking it for others to grab. Duviri Experience is enjoyable except for Undercroft, and with the force dragging part it becomes one of the biggest Duviri killjoys, and Circuit is the better place to farm Rune Marrow anyway. Removing Undercroft from the main objective of Duviri Experience would let everyone freely roam acroos the plain without interruption and greatly smoothen the Duviri experience