Personally, I wouldn't want the encounter itself to be directly nerfed; while I certainly wish it had been designed differently (from a standpoint of making the encounter itself more enjoyable to me, pass or fail), it is what is it and it would be pointless to change it.
What I wouldn't mind seeing in this case though is a determination buff (though not on the scale of LFR's.. more along the lines of +1% per attempt and requiring dropping Kanrethad below say 50%, or reaching a certain stage) that would be cleared upon leaving the instance or voluntarily by using an option on the anvil. Win-win, imo. Those that like this type of challenge aren't bothered and those to whom it is nothing but a bottomless font of unenjoyable frustration have a means of eventually getting it with enough effort. The only people that would have a problem with it are the ones who somehow feel their own accomplishment is diminished by others having fun and quite frankly, screw those guys.