Your analysis is insightful. Your attempt at a solution is problematical.
How to solve this? (If it is even remotely possible...) Demand that children are COMPETENT in critical thinking and understand that the underlying principles of this country are about taking the RISK OF LIBERTY, that government DOES NOT SOLVE PROBLEMS, and to take personal responsibility for things around them.
Problem is, who makes the tests? What is competency? Who gets to define it? Do you really think you could get a set of wingnuts in a room to actually agree about something?
I can't think of anything about education that isn't problematic. There is nothing about our education system that isn't problematic. It is a hierarchy of rolling disaster. (The first thing is to fire 1/2 of the administration. Education is WAY too expensive because we have more people "administrating" instead of sitting in a classroom in front of students.)
Testing is always a problem but you have to have some basis for finding out if the efforts of education are effective. Otherwise you have headed into the new-age nonsense of pandering to children.
There are specific techniques for creating good test questions. You simply look at the responses to individual questions and see if they statistically differentiate between students with a higher and lower level of comprehension of the subject matter. If a question doesn't tend to distinguish between a higher level student and a lower level student then it is a bad question and should be discarded. A test can then be effectively designed with a range of questions that tend to differentiate between the different levels of A, B, C, etc... students. And the number of these questions is designed to generate the grade dispersal you require.
As far as dealing with the "wingnut" issue, that is where the drastic reduction of administration comes to bear. Having the number of people in positions of administrative authority that we do we automatically end up with that many people applying "power". All of this action without being in front of a classroom is insane and we are paying $$$ for it.
We currently have a system where instruction is simply targeted directly at standardized tests. No "teacher" thought up this stupidity. It came from administrators that look at children and see how many $$$ a day of funding they provide and the results of standardized tests control that funding. "Stupid by law..."
I can tell you a very simple test for an understanding of the underlying principles of this country and competent critical thinking: Someone should be able to effectively argue a position that they adamantly do not agree with, and they should demand that someone else should have the right to speak a view that they personally find objectionable.
I agree with you about the personal responsibility bit. I disagree with the categorical shout about solving problems, because all it takes is one (1) instance to disprove the opinion.
The shout comes from the simple fact that the job done by federal (and most state) government(s) is so bad as to be laughable. If you had a teenage child that had the same fiscal responsibility and ability to dance around the truth as the government you would ground them for life.