Nerfing leveling dungeons would simply create more players who don't know what to do, but think that they do because they did the leveling needed.

This game has so many fast ways to level including the upcoming jumpm potions, it's completely unnecessary to nerf existing leveling dungeons.

Like KisaiTenshi I'd really like to see level sync beefed up to be more of an "original difficulty" mode as well. It's funny, after running more higher level dungeons and content and getting used to the higher level skills and rotations, going back to something like Darkhold can be a bit jarring as you are reminded how you are supposed to play when you don't have all the 'big' skills. Perhaps making level sync closer to that original difficulty would help people improve by reminding/teaching players how to handle things without overgearing and without uber-skills.