The fact is it is a WCS, and not only that, but tthe highest WCS wins that appointment. A 28 on one slate with your athletic ECs may be high enough to win the nom., but on another slate it might mean your WCS is number 10 out of 10.
There is no way to give you a yes or no because the slate you are on matters too. Your post leaves that portion of the equation out. I.E. No Virginia is one of the most competitive areas, a 28 even with a state championship might not be enough to overcome the ACT. In Fairfax VA, the median score for HS students is 30 or 1350+ SAT. PAR is 60% of the WCS. In NC the score for Goldsboro is probably around 27, thus having a 28 makes you very competitive when you add in the state champion.
JMPO, but I am with tug on their point about academics. You may win the appointment with a lower ACT, but the fact is the ACT/SAT are national exams that illustrate your academic foundation up to this point. College is going to be moving at a much faster pace than even your AP classes. If that foundation is not there you can quickly find yourself behind the power curve. Professors are not going to slow down the pace of the class because you are having trouble grasping the lesson.
If you have looked at the AFA curriculum you will see it is chockful of Math and Sciences for all four years regardless of your major It is not jokingly referred to in the ADAF as The Little Engineering School in the Rockies for no reason. Thus, at the end of the day make sure you feel you have that foundation.