A lot of people have criticized the 'DC by Level' chart in the 4th edition Dungeon Master's Guide. This is basically a chart that tells you what DC in a skill check would be easy, medium or hard for a character of a certain level. The problem isn't really with the chart itself but with the fact that it tempts rookie DMs (myself included) to set any DC in the game with an eye towards their character's current level. In other words, no matter how much the characters level up, they still haven't gotten better at anything. This kind of blows.
The solution, in my opinion, is to take the DC by Level chart as a guide and extrapolate a bunch of static DCs for common actions that can be prepared in advance. This way, the DM has a strong resource to rest their rulings on and won't be tempted to get all quantum ogre-y.
The other advantage of such a resource would be that you could make it open to the players. This would encourage them to try more interesting maneuvers because they have a whole bunch of suggestions, and they even know exactly what their chances are of success.
But writing up so many DCs is a pretty mammoth task! If Wizards of the Coast were cooler then they probably could have done it for me; it certainly would have been a better use of their time than, say, the Bladesinger. But still, I'm going to give it a shot, going through the skill list alphabetically.