There already is some discussion in this thread.
But thanks like always for the great polls. 
And although I think, overall the event is balanced I can understand and also support that those bosses, especially in the last epic levels don’t work.
They are extremely hard to kill and on the same time their special are devastating.
I mean I won’t bother if nothing changes, and most of the time I also like a good challenge, but if there is too much frustration for too many people that’s not healthy for the game itself.