I ride daily into London and back again from Kent. Hi-viz is fine, but its best use is in the dark when the reflective strips work, not for the day-glow yellow in daytime. I do wear one, but after 5 days its so filthy that the yellow is faded anyway.
As to accident rates - yes, most are avoidable, and yes, bikers riding like eejits are just as responsible for them as car drivers who don't look. If I was to sit in traffic like a car and roll slowly round town like a car then I would be alot safer. And slower. And I might as well be in a car. Riding a bike is about getting from A to B quicker than a car, not getting from A to B as quickly as a bike will let you. Filtering is part and parcel of that, and with the increased speed comes increased responsibility for your own actions - a copper will not stop you for filtering unless you do it insanely fast, but have an off and it will be 50:50 even if the car driver didn't look, for the simple reason you technically shouldn't be there. I find the worst offenders are young kids on scooters, who have no respect for cars, bikes, cyclists or pedestrians, and seem to have the best job in the world judging by the speed they want to get to work in the mornings. Most of these are 'local' so they don't have any big roads to get the speed out of their system before being in London. I have 50 miles of motorway first - the last thing I want to do is filter insanely fast after that.
As for the fashion argument - evolution in action. If you want to look cool, you might just end up cool - in a morgue locker. Do what you can to stay safe and sod the looks. Hi-viz - no problem with that. Compulsory protective clothing - fine by me too. I also use halogen bulbs as headlights and have them on at all times (road legal, not the lighthouse style ones on e-bay!). Flashing lights - no problem with that either - make mine a blue one please!
Steve