After classes have been pruned more and more to only give a full, proper gameplay experience at max level, I am kind of inclined to agree that there needs to be something done with skill synching in general.
Whenever a expansion released, we already always had an endgame level rotation available to us in dungeons, after all, and the following leveling dungeons were kinda made with such a rotation in mind already.

Skill potencies can be dealt with easily enough. CS3 know what PPM they had in mind when creating a dungeon, so capping PPM (like a reverse echo) would be mathematically easy enough. Like I care if Johnny Greensprout does the same damage as me using only 4 buttons, I like using my full rotation.

There are however skills where capping PPM would do nothing because of how they work (like WAR's bloodwhetting,or the amount of oGCD healing healers have), which would need special attention and a different solution.