It is certainly more preferable to get a bunch of new stuff, but when you compare the time it takes to design an entirely new dungeon vs. upping the level / damage numbers on the mobs in a dungeon, it becomes exceptionally time efficient to re-release old stuff. Now, if all we got was re-released content, that would terrible, but that's not what I'm proposing.

With each content release, if we got 1 or 2 of the 61-69 dungeons at 70 as well as maybe 2 of the old, less played 50 (Hard) dungeons, we would get a lot more queue diversity for minimal time and effort input. Furthermore, there is also an extreme lack of 51-59 dungeons getting played. I can't remember the last time I played The Vault, but that was probably my favorite dungeon so far... but since it is leel 57, it never got that much play outside of people who leveled multiple classes through dungeon grind as opposed to other methods.