More Interesting Tank-Centered Graphics Effects...?
Let's start with a few realizations. Interactions with mobs are probably 99% with the tank. Sure, melee dps & ranged dps do their thing but they're not really interacting with the boss mob.
Second, World of Warcraft has taken an almost comic level of graphics. Like it or love it (I assume you don't hate it since you're playing the game) the graphics are cartoony. Personally, I love it. It's the best ever!
With that in mind, why aren't there more tank-centered graphics effects? You could have a screen shake effect on a critical block. You could have some type of very slight slow mo on a critical shield slam. How about some more dust & maybe some rocks falling from the ceiling when a thunderclap shakes the room?
Most other players wouldn't need to even see these things. It could be tank only effects. Maybe there would be a toggle effect for other players to enjoy what it's like to be a tank.