Don’t take my word for it – read what JD Wiker has to say. In the comments there’s some good points from other notable game designers – Sean K. Reynolds, Stan!, Monte Cook – who have basically been kept away from the 4e rules. Why is this? Wiker wrote Sandstorm and contributed to the 3e PH, MM, and DMG. So did Stan!, as well as developing Ghostwalk, Player’s Guide to Eberron, etc. Sean did lots of 3e FR stuff, and the Big Three too. Monte did the 3.5e Big Three.
Why is WotC keeping them out of 4e? Morons.
Geek Related 
One Word. Hasbro.