Governments rarely make public their criminal acts or keep records on the number of illegal acts they have committed. Governments that engage in assassination conspiracies, terrorist acts, and other crimes to further their foreign policy also commits crimes against humanity.

Eisenhower administration campaign to overthrow the democratically elected prime minister Mossedagh in Iran and replace it with the monarchy of Shah Reza Pahlavi who in return promised US oil companies control of over 50 percent of Iran's oil production. The CIA engaged in a massive assassination conspiracy and placed Shah in power. On June 5, 1953, 6,000 Iranian citizens were murdered in one day. No country in the world has a worse record in human rights than Iran, and it was caused by the US oil companies greed for profit. In 1979 the Islamic revolution took control of Iran and was anti-American for the killings of their Islamic brothers. Heavily engaged in the sponsorship of terrorism aim at the US.

The US is not hated for its power, the US is hated for the acts committed.

Now to answer your question: No, we should have not killed Saddam. It will become another "Blowback." Life in prison would have prevented more hate toward US policies.
Should we have killed Eisenhower for his acts against humanity? 6000 Iran's were slaughter.