The new Criterion project that Webster is leading is the same project that has been spoke about after the changes at Criterion that saw the studio slimmed down to a focused team of 15 people or so as the rest of the staff moved over to Ghost Games which is the new EA studio that is handling the Need for Speed franchise.
As to why Ward and Sperry elected to depart for this new venture is somewhat a mystery beyond the Tweets indicating the new studio and project that they are working on. Ward will also be splitting at least some time from the new project to writing a monthly column for Develop Magazine. It is not clear from what we have been able to ferret out if anything else contributed to the decision to leave or not.