Well, I'd prefer people driving near me have mirrors on their vehicles. My 76 Range Rover didn't have a passenger side door mirror, was it safe and cool not to have one, I didn't think so and wasted no time fitting one.
As far as intrusion bars goes, nice in theory but that also means anyone could just rip the doors off a 68 Kingswood or any other pre-intrusion bar vehicle and and drive around without them as long as they fitted a drivers side mirror as most cars that age didn't come with a passenger side mirror. You could probably drive around with the windscreen out on one of them too as long as the rearview mirror was still in place and maybe you fitted a deflector. I've driven a Landrover with no roof in the rain and even with sunglasses on it's not cool, windscreen or not, you can't see where you are going safely. Motor cycles have full helmets for a good reason or decent goggles
Good luck with the magical approval document from Main Roads, because AFAIK no one else has anything in writing yet, you might be able to get a engineering mod plate for it perhaps?
I would love half doors myself some HD alloy checkerplate ones would be nice, as even offroad I see the need to keep my legs functional. Some protection is better than none.