#5 - Feb. 15, 2014, 2:46 a.m.
Why are challenge modes being disabled before the expansion until next expansion? hint at new leaderboard tech?!!!!!!!!!!!! :)
The full explanation is in the blog. The short of it is, Challenge Mode is based on it being a challenge with current mechanics and, lots of mechanics will be changing in the pre-expansion patch.
With Warlords of Draenor’s class changes, itemization changes (e.g. the removal of Hit and Expertise), and—of course—increased level cap on the horizon, the difficulty of Mists of Pandaria’s dungeons will no longer be tuned the same as they were. In the spirit of fair play, when the aforementioned patch is released a little while before the new expansion launches, the current slate of Challenge Mode dungeons will no longer be available, and the achievements they award will be converted to Feats of Strength.