1) This mechanism is already present in the current electoral system and is very evident in the election of Trump.
2) This is the reason to only replace 25% if the parliament per year so that not all experience is lost. It gives more power to non-elected public officials which can be good or bad.
3) By removing reelection you also remove career politicians and reduce corruption. No need for campaign contributions or campaigning promises. Also, the drafted people would go back to their social circles to be judged by their peers after ended term of office where they would have to own their decisions.
1) Not nearly to the extent it would be. Unless you'd like to take the viewpoint that the upper class don't buy better educations than the rest of the country.
2) You still have a maximum 4 year experience level. As someone who grew up in a college town, I'd estimate having to explain the basics to 1/4 of the elected body every year would require significant resources.
Additionally, handled incorrectly, you imperil the stability of the legislature. Imagine if every year were Trump election year: Mr. John and Ms. Jane Doe go to Washington intent on toppling the system as it stands because they're unhappy with the way things are.
3) Fair, but the social censure of being judged is a few orders of magnitude smaller than the power these people would wield while in office. If you think politicians are corrupt now, imagine if Exxon offered $x million in bribes to an average person off the street to approve oil drilling in wilderness refuges.
There is a lot wrong with the wealthy monopolizing political power, but at least it semi-insulates them against outright financial persuasion.
1) By taking the average, you are risking compounding educational decreases in the populace.
Bad public education policy is enacted, chosen politicians become less educated, worse public policy is enacted, etc etc.
2) By using less experienced politians, you lessen the efficiency of the entire political process.
3) By not having the possibility of re-election, you remove any responsibility of the elected after they're elected.