I would like to make a simple plea to high schools: don't offer ap classes at the expense of offering a full complement of normal, high quality hs courses (precalc, etc.). The incoming freshman I see are more and more often victims of schools where, for whatever reason, precalc is not encouraged or even offered, but you can take ap calc. Or precalc is taught by the coach abc (who had a math class once) but the real math teacher is teaching ap calc.
I recently asked one such student, "what is (cosx)^2 + (sinx)^2?" Eager to demonstrate what he'd learned about derivatives he said, "-(sinx)^2+(cosx)^2." Instead of being ready for calculus, as he surely would be if he'd taken a good precalc, he needs at least one semester of remediation (probably two) and he has misshapen notions that will hobble him when he does take the calculus course.
There are many marvelous topics that can be covered in precalc, parametric and polar equations, iterative methods, programming - why forego these fundamental concepts for a cheap thrill status trip? If a student has "done" precalc, but may not be ready for a sophisticated calculus course, give her more - combinatorics, probability and statistics, finite math - pour it on.