Actually, I don't think that will happen. Larry Lindsey, the other guy canned with O'Neil, has been a goo soldier and not lashed out. Others that have left, including Ari Fleiser, left on good terms. There is a thread of loyalty in those that have been with Bush before. O'Neil was always an outsider.
Maybe with former Bush Administration officials. Once the media runs out of those, they have an endless supply of cranks and malcontents who have never been within 1000 miles of the Bush White House, but have some marginal connection to the president and are all too eager to spew Bush hatred if it guarantees them some TV time. If the media could find a second grade classmate of George Bush who claimed that Bush once shoved him on the playground and stole his lunch money, that classmate would get saturation coverage.