In my opinion Dynamic Events that determines if dungeons should open or not is a terrible idea. If I wanted to plan a dungeon raiding on Friday with a group of friends because it is the only day we can get on to play GW2 and then find out that the dungeon is closed, then we may never ever get to play the dungeon together for a long time.
Guild Wars 2 was made for people that has lives. So that we can choose when to play when we can or if we want to. Dynamic Events should not influence if dungeons should be playable or not.
Most of the time, Dynamic events that do influence if dungeons opens or not remains closed or was bugged.
5x Warrior, 5x Ranger, 4x Elementalist, 4x Engineer,
4x Necromancer, 3x Mesmer, 4x Guardian, 4x Thief, 4 Revenant