Nukers enjoy a massive mana pool, which allows them to cast any spell they want. However, they are easy to kill if they don't expend any of that energy on defense. Ergo, Monks have to mitigate the significant amounts of damage nukers take when they decide to join a slug-fest.

Ironically, Elementalists can practically disregard the stat penalties from dying, because they will still have a serviceable energy level.

Notice that Miss Healbot is toting a backpack full of salvaged wood planks, and the ArenaNet Frog is observing the Nuker dancing...