I think they toned down Shadow Behemoth at some point after launch. There were more AOE circles and they hurt a lot more when I first encountered it. The Fire Elemental in Metrica got majorly toned down, but people also started to figure out the actual mechanics. The first few weeks that thing was a graveyard. Now the fire adds don't really matter much.

The giant bosses do have mechanics, but event scaling just can't keep up with the massive amounts of people there. The way people found a way to trivialize stuff like the Shatterer ruins the entire boss fight. Claw is the only one that forces you to have to play out the boss fight mechanics. Well I guess Grenth Temple does as well.