I understand what you are saying, however I think that you are missing the bigger picture here. First off the challenge in this game has always been more or less player imposed. New content is released some of which throws players for a loop for a short while and then strategies are devised and lead to commonplace methods of completion. I remember when people complained to no end about the changes made to CoP and how those changes somehow rendered the progress previously made by players worthless. It was a lot of BS in end. SE looked at the numbers and determined that there were obviously issues there if only a small percentage of the player base had progressed through the content. Achievements are and should be in the eye of the person that accomplishes them. The same should true to challenges in this game.
Although the situation with dynamis is slightly different as this is revamping old content that is seldom used, it still doesn't change the fact that at this stage in FFXI's life cycle SE needs to do what makes the most sense to keep the majority happy. I love FFXI as much as anyone else, but that doesn't change the fact that this game is still old and things need to be changed from time to time. I'd rather have some aspects of FFXI changed than to not have the game at all.

