Are there any negative consequences to an instructor attempting to achieve "all A's from everyone"?
No, there are no negative consequences.
The key is this sentence right here:

Assume that students only earn an A by demonstrating that they have
achieved the course goals

That being the case, grading becomes evaluating the following:

If everyone in the class is able to do everything that they should be able to do... mission accomplished

Edit: I teach pilots how to land airplanes safely.  Students only earn an A by demonstrating that they have achieved course goals (they land the plane), and I never lower my standards for anyone (you don't get an A unless you land safely).  As for the third criteria, I don't make students explicitly aware of my goal, but let's face it, it's implicit in the training.
My argument comes from seven years of personal experience:

Are there any negative consequences of me making sure that all my students are able to land the plane safely?  No.
Are there any negative consequences of me not making sure that all of my students are able to land the plane safely?  Yes: flame and then newspaper headlines.