Here is a new way for candidates to run for POTUS, maybe even an orginal.

[enlightenment]

11. You are conflating two different things.

Your idea is that two people decide to run as president/v. president, having made an agreement (in secret) that, should they be elected, halfway through the term of the president they would switch places.

That has nothing to do with the electoral college.

Yes, electors are the official mechanism by which the president and his/her running mate are elected - but officially their job is only to confirm the majority vote of their state. They don't decide what the presidential term of office is, nor how the president is replaced - if necessary.

As far as Nixon resigning - he didn't "break anything wide open". He took an avenue afforded by Article II - and his successor was chosen by that same mechanism.