The strategy behind tuition pricing is to charge every student the maximum they can "afford" (or the numbers say they can afford) to spend. See http://chronicle.com/blogs/conversat...et-price-myth/ (very good comments to the article, as well.)
IMHO, that is a foolish way to purchase anything. I suppose in theory a family making $150-200K per year could afford full freight at WFU for their kid(s). However, that seems like a foolish waste of money because the family also needs to save for retirement and might have life goals in addition to sending their kid to a country club university.
Wake is no longer a rational choice for upper middle-class families. I don't know enough about the student aid to say whether the price gets low enough to make it a rational choice for lower middle income families. However, Wake would be a rational choice for lower-middle income families if, after discounts, it is priced at or below the cost of UNC.