I honestly believe that there should be a certain line drawn. DC-3 flights are not really public transport, ie you just catching a flight from A to B paying normal fare etc. Those are historic flights which are designed for aircraft/aviation enthusiasts, most of them are perfectly aware that they flying something special by all means. There people going to Iran just to have a domestic flight on one-of-last-in-scheduled-service pax 707, there a people flying from Damascus to Caracas just for a sake of ride on 747SP, there are people paying for MIG or SU jetfighter experience etc. None of them are EU-OPS comliant and will never be.
As a part of solution (although not in line with EU-OPS, but something as a ground for dispensation by UK CAA) passengers on such a flights could be briefed about what kind of disperances this aircraft have against EU-OPS and then asked to sign "release of liability" and still 90+% of them will sign because they know exactly what they want.
p.s. S76Heavy - very good point about classic cars. Or even about just a bit older cars, ie no ABS, no ESP, no airbags etc - very dangerous to drive! But still not banned....