ArenaNet has already taken the stance of waiting for players to adjust to the current state of the game before making big changes to skills and overall balance in Guild Wars 2. That mindset, as laid out by Game Director Colin Johanson in a forum post, is also being applied to dungeon difficulty. Rather than rushing to adjust to initial player feedback, ArenaNet devs are taking the long view and waiting for players to get used to the game and its difficulty. They took a similar approach with the original Guild Wars' dungeons and elite areas, to eventual success. Johanson talked about player outcry when the Domain of Anguish was first introduced and how just months later, without real balance changes, "people viewed it as the most fun thing in the game." He went on to explain:
We're actively monitoring every dungeon and working on balancing issues we encounter appropriately. We'll be keeping an eye on bosses we think don't have enough varied mechanics to warrant their large health pools and updating them over time to make them more varied/interesting fights. We'll be monitoring, and continually tweaking/adding to dungeon rewards over time and of course balancing where we see the need. And of course, we'll be looking at adding more dungeons as well!
All of that being said, the game is VERY new for most of our players, and I can absolutely promise with more knowledge of the game and advanced player skill, the explorable dungeons can all be overcome by being skilled groups. We've seen many groups do it just fine in our internal alpha test once they had time to learn how to play the game well. Just like Domain of Anguish in [Guild Wars], it takes time and practice to learn how to overcome stuff as hard as our explorable mode dungeons, and that's exactly the kind of players they are designed for.