Please do not nerf content!!!
The classic mmo experience is wiping to a boss and learning its mechanics/improving your character until you can wipe the floor with them. There is no feeling quite like it.
Making all of your content easy will remove the need for progression or improvements. All bosses will become as easy and forgettable as the ones from the story quests.
An alternative solution could be to promote content that explains mechanics or have your company do an overview of an area or boss on twitch or youtube.
You could potentially make money from this avenue instead of jeopardizing the longevity of your game.