Contolling the head cockroaches won't keep the 15 billion other cockroaches at bay...
The CIA, like almost all government agencies, has becomecorrupt and political from top to bottom. It would take a massive purge to get it clean.
It will take more than a "serious purge" I fear - IMO it will take the creation of a new agency, with hand-picked top staff and a loyal rank and file.
The CIA has become an independent foreign-policy making group, and as was said earlier, a few loyalists at the top cannot stop the spread of insidious leaking and disinformation coming from the disloyal ranks.
This is a story that needs to be told again and again until it gains recognition.