^ this section should have been in the first few paragraphs imho. Explaining why this is relevant shouldn't be so far down.
Explaining the value of what you are showing should always go towards the start. Else, why would anyone bother with the rest?
Giving such a blanket "responsibility" to the author at all is just such a bummer! I say let them do whatever they want, there is always more than one way to express oneself. Someone who was never taught to write a clear thesis in the first paragraph for whatever reason doesn't inherently have less to say.
Never heard of Abstract section? First semester on a college or last year on high school.
Haven’t you dramatically overstated your case? Many expositions do not contain an explanation of their value at all. Works of fiction are a good example, and there are many many others. Often it’s the responsibility of the readers & reviewers to decide on questions like value.
As a professional mathematician, I rarely need to worry about the correctness of a paper. The main difficulty of writing a review is instead understanding what the results of the paper mean in its context, how the results are presented, etc.