Before the 12th amendment, the presidential candidate who got the second most electoral votes became the vice president. This meant they were usually different parties.
It occurred to me that one thing this achieved was always ensuring that there was someone in the room who would be willing to disagree with the president. He couldn’t surround himself with yes-men.
I think it depends on the administration. They certainly should be given line of succession. Their main purpose is to carry on without missing a beat.