Alright, this posting is after attempt number 3 on this boss.
This boss needs a tune down. I know some people are going to shout "challenge is good" and "scale it down" and what not, but I honestly don't care about that useless banter.
The fact is, one of the mechanics is either broken, or needs tuning down. Here is the problem, Big Rabbu, the Widow-Maker, and the Whisperer spawn at the exact same time, and the big boss activates while they are still alive. So, my group has essentially had to deal with 4 bosses at one time, and the amount of damage and abilities going out from the bosses is just over the top. I don't want to imagine ZOS designed it this way, because its a dungeon, not a trial.