Problem is that there are a minority (I think they are a minority) of people who strongly object to "intrusive" scans, pat-downs and profiling, and groups like ACLU that have the means to tie up in courts any effort to enact them. They will do anything to block or make safely measures time consuming, so that they will not be utilized. So, I think the realistic response is to give them the option to have things their way, while allowing the majority to comply with safety measures.
I thought of another group of flyers: Those who refuse scans but allow pat-downs. As the latter take more time to complete, put such folks on separate flights, with instructions prior to purchasing the ticket that having to pat-down everyone prior to the flight would likely cause delays, and the purchaser of such ticket acknowledges the likelihood of delays and holds the airlines harmless when delays occur (all language done by staffs of attorneys, stated repeatedly in several languages, the purchaser having to initial acknowledgment multiple times showing what they have chosen and all implications to those choices -- so that the purchase agreements hold up in any court).
So, we get choices: 1) Agree to scans, and follow-up pat-downs as deemed necessary, and fly the most direct routes with minimum delays. 2) Refuse scans but allow time-consuming pat-downs, and fly the most direct routes but with likelihood for flight departures and arrivals. 3) Refuse all checks of one's body, allowing scanning of bags only, and fly on planes that are diverted around high population areas, and accept the increased risk of a tragic outcome (hopefully the ACLU staffers would choose this last option!)