The fact is this event is great in design but it's designed for more people than there's on the maps. That's the realy issue there.
When you fail it for the 12th time, and you can't finish your main story because you want to get the map achievement... Which I don't have yet, you are screwed.
The fact there's difficult content isn't an issue for me, but you can't have the end of the story being stuck behind such a wall. The last combat of the event is great (when you can reach it, as preparation aren't always full) but it's not balanced out.
And add to that map crashes when you are at 10% of the boss life, and you want to k*** yourself.
So yes don't nerf, increase the number of people on the final map for f****** s***... Ah... I forgot... the map will crash if you do so. So then yes, nerf the difficulty to be on par with people actually doing the event...