The Office of Professional Responsibility, which is a group entirely comprised of careerists, recommended McCabe's firing. If a political appointee attended, one could make the case that the decision was political.
The FBI has a very strict policy that anyone who deceives will be fired. This has been done many times to lower-level Special Agents. They must tell the truth and accept punishment for anything done wrong. The question was whether or not OPR and Sessions had the balls to do the same thing for those at the top. They did.
McCabe can file a lawsuit in court requesting his full pension be reinstated. Some attorneys say this won't work because each person is informed during initial training that deception is a fire-able offense.