This is an idea that sounds sensible on its surface, but it relies on the theory that it's the politicians that are the problem. It ignores how politics really works, which is that politicians mainly take the positions of the key coalitions to which they owe their power.

This is not a simple concept. Here's an example of how this system breaks down. For instance, in the United States, the Black population has a big problem because the Republicans actively attack their community which means they stick to the Democrats reliably. However, because they can't switch their votes, the Democrats ignore them. Notice that this explains the predicament of the Black community without reference to individual political personalities.

On the other side of the coin, the NRA manages to control the fealty of Republican politicians because it has major influence over voters.

https://www.nytimes.com/2018/02/24/us/politics/nra-gun-contr...

The politicians line up even in the face of screaming children whose friends have been murdered. That's a tough job. That must mean there are substantial incentives for them to do so.

In summary, if you rotate the politicians in the manner you suggested, you actually give the corrupting elements more power rather than less.

EDIT: I would be negligent to say that the Democrats merely ignore the black community. e.g. Hilary Clinton's "superpredator" comments in the 1990's that backed the crime bill that vastly inflated the prison population.