SE should leave the overall difficulty of CM, WP and AK unchanged. You have to have a base starting point for new level 50 players to jump into end game content. Together with Ifrit HM, these 3 dungeons are where you do that.

Instead of just saying we are going to make these dungeons drop more tomestones, or adding mythology tomestones to CM and WP, but in order to do so we have to raise the difficulty, why not add bonuses that will give additional tomestones. How about adding a bonus of 10 tomestones for opening all chests in a dungeon? Maybe adding 20 tomestones for killing every monster in the dungeon. You could add a 10 tomestone bonus for clearing a dungeon without any deaths. There are ways to make the content more rewarding and making them be completed how SE intended them to be completed without raising the difficulty.