While I wouldn't like more content like Rath Extreme, it's not due to the fight itself or the "direct challenge" it provides... it's due to what it allows.

The four man extreme system allows you any group comp, which allows folks to single out classes, and than it's designed to also punish the healer job in particular to the point where you're better off "cheesing it" (which in my mind kind of "invalidates" some of the challenge but that's a whole different topic). This is the part that I don't really want to see again, although I'm pretty sure it was done in particular to further emulate Monster Hunter and we won't see such a thing again.

That being said though this fight does promote personal accountability for surviving which is far more refreshing than the constant personal accountability for DPS, and some of the parts of this fight (although I've only watched extreme but hard emulates enough of it for me to have drawn this opinion) are refreshing only because we don't do them in every single dungeon/extreme.