The issue is that your magical fight that has few mechanics but is still difficult doesn't exist. Bismarck was not hard, he was a Patchwerk with some simple "dodge this" mechanics thrown in. That's not difficult nor is it even remotely intuitive.

Real difficulty in a boss encounter comes from being able to master various difficult mechanics while also performing your role perfectly. You take the various difficult mechanics out and all you have left is a boss that only requires you to play your class properly and then hands you loot... like Bismarck.