I have been reading Tim Weiner's excellent "Legacy of Ashes", a history of the CIA. Everyone should read it; it won a national book award and is generally well-researched and sourced.
What it indicates is that the CIA is essentially a long-running unconstitutional operation, and that every president since WWII has made use of the CIA to conduct covert actions in foreign countries that are entirely illegal, including operations like subverting elections, deposing governments, assassinating foreign leaders, running drugs, and more. Every President should basically have been impeached for running these covert actions, the Constitution has no authority for the President to wage undeclared wars and conduct hostile actions whenever they feel like it.
There is another branch of the CIA that conducts intelligence analysis; there might be some room for this half of the CIA, but this function has always been secondary, and has the problematic history of constantly tailoring what it says to satisfy the political demands of the President or Pentagon.
We'd be better to replace the CIA with a new agency, one which doesn't conduct covert action, and whose mandate is to make public intelligence assessments (because the public needs to be informed of these things in a democracy) rather than secret ones. The clandestine nature of the service should disappear entirely.