From the Wizards of the Coast Website:
“We recognize the important role third party publishing support plays in the success of the 4th Edition of Dungeons & Dragons. We have listened to the community and our valued colleagues and have taken their concerns and recommendations to heart. Our commitment to the health of the industry and hobby gaming lifestyle is reflected in the revisions to the Game System License.”
--Linae Foster D&D Licensing Manager
One can only assume this is because of the considerable negative press the GSL has been receiving, and the number of companies who are either refusing to publish 3rd party 4E material (like Green Ronin) or are planning on publishing 4E material under the auspices of "fair use". It will be interested to see what the revisions are, and how publishers will react.
