So wait are the dreamers actually impaled on icicles or is that just imagery. And does that mean that these dreamers die at the hand of the dreamer version of the Others or do they die from the equivalent of dreamer exhaustion?

I think it’s one of those psychic death things. Remember, Bloodraven is reaching out to people already in grave distress from injury and disease, so I think a lot of them simply never wake up. We don’t see their deaths, because they’d look natural, ordinary.