... an outgoing prez should no longer have control of the major levers of presidential power. i.e. nuclear codes, military/Pentagon, DHS, etc. All decisions about departments like that should at the very least be required to be collaborative with the incoming prez, with final decision being solely the incoming prez's.

I don't know how that would work logistically, but we now know that outgoing repug presidents can't be trusted not to be nazi. Hopefully we learn our lesson quickly.