Actually, CIA should have considered many possible scenarios to deal with Assange. Just because some leaks were beneficial does not mean he should be trusted with more.
Actually, there is no evidence that Assange did anything more than what the New York Times did with the Pentagon Papers. I don't believe assassination is the proper response to a journalist who reveals criminal behavior on the part of a government agency. Imagine assassinating the editor of the New York Times.
While I do not see proof that the CIA/Pompeo considered plans to assassinate Assange, I would be surprised if the CIA did not consider such a course of action following the publication of the Vault 7 leak to the public. The CIA redefined WikiLeaks to be a "non-state hostile intelligence service." Wikileaks may be the first intelligence service to publish its intelligence scoops to the public.
CIA routinely considers all possible ways to deal with such threats, as it should. I would think it is not doing its job if it does not consider eliminating such threats even by assassination.
I will say furthermore that if there are Americans supporting such threats, aligning with members of foreign Libertarian party elements, as well as spy elements, and engaging in deceptive campaigns against patriotic leaders such as Pompeo because he stands in the way of international libertarian and socialist comspiracies, CIA should consider all possible actions against them as well.