It´s almost impossible to find a vet dungeon grp that is not pledge (currently queuing for Graven Deep to get my last slayer ghosts for 80min PCEU on a Sunday, yesterday was not much different). In the worst case you have to wait for a whole month to have your dungeon come up as pledge.
With the ever increasing number of DLC dungeons (a good thing) the wait time for a specific dungeon is getting longer. With the introduction of a second Questgiver where 1 is offering the first dungeon of a DLC and another the 2nd this wait time could be halved. Having 2 DLC dungeons might also support group building and player interaction since it´s worth more playtime and keys to set up a grp instead of running super boring base game dungeons.