I mean, honestly, trading 3 dungeons (maybe 2, if 4.55 has a dungeon) for more experimental content is a no brainer, sure Diadem crashed and burned, but at least they tried to make something new there (also, it's timing in the expansion kind rendered it pointless anyway). On the other hand, you get Palace of the Dead, which is a fantastic piece of content and feels pretty integral to leveling now. I don't think I'll really be that bothered losing 2 or 3 dungeons, since, I just daydream through them anyway after a week or two. Basically at the moment, the only variety I feel a second dungeon brings is a new background. In any case, I believe Deep Dungeon will be expanded on throughout the expansion anyway, which is a dungeon in of itself, just with a different twist.