Exactly. I have a hard time imagining the circumstances under which an uncurved exam does a better job of distinguishing among the students.

If the top five "A" students on a curved exam score: 93, 88, 85, 83, 78 -- then on an uncurved version of that exam the same "A" students must score (hopefully in similar order) 99, 98, 96, 95, 93. So the uncurved exam must have two weaknesses by comparison:

a) It is objectively easier (the same 5 students got more questions correct)

b) the relative order of the student's exam grades will be more subject to the small nuances of stupid mistakes and minutia memorized, since the difference between two adjacent students was probably 1 point (on a 3 hour exam) rather than many.

So a heavily curved exam would not only be more rigorous, it would have a much more repeatable result. And isn't that our holy grail?