Many current and good endgame tanks will tell you it isn't really all that fun. Also the idea that many fights can be solo tanked when SE is clearly designing the game for a 2-tank paradigm seems a bit wrong.
Although they probably won't change the game on account of a forum post, I'd still like to share my thoughts on what could be a more interesting or challenging way to tank.
My first point is that enmity is rather a simple thing to handle and achieve. It's not hard nor interesting (especially for paladins).
My second is that as your gear increases, endgame bosses become trivial in damage done to you.
My third is that since fights are being solo tanked, it reduces the desire for two tanks in a group, which is a bad thing for the tank population, as they are less needed and therefore more likely to roll something else.
So what if a mechanic were introduced to force you to be more intuitive about how you control damage done to yourself?
Here's what I suggest: Battle Fatigue. A mechanic that slowly causes you to take more and more damage the longer you tank something, and increases based on the rate of damage you take. Doesn't have to be a huge amount, but enough to cause you to control or think up of creative ways to reduce the amount of damage you are taking.
And then while you are not tanking, you recover from the battle fatigue, perhaps stacking even higher defense proportional to how long you have not been being railed on by the boss.