You probably need to back up a step and ask what an A is supposed to signify. If it is pure mastery of the material, and the test-takers are bright and diligent students, and if the prof did a good job of teaching the material and designing an assessment that tests mastery, it seems reasonable that many students will indeed show mastery of the material and earn an A.
If, otoh, the A signifies that they received one of the top 7% grades in the class – the “grading on a curve” that was so familiar to most people my age – then there will likely be no grade inflation. It may also require an assessment that includes application of the subject matter in a way that is very challenging and perhaps novel to what has been covered in class. It may also mean that mastery of the material is a given, not what is being tested.
Personally, I have no problem with the first model. But I do have an issue with any model that allows for grade revision through re-takes, extra credit/work, etc. While this may help a student master the material - the objective! -, it doesn’t change the fact that at the point of taking the exam, that mastery wasn’t there.