My gut reaction is that MOT exemption is a mistake and will have unforseen consequences.
But I also accept that older cars need experts in old cars as testers. At least old cars don't do much mileage, and it would be easy to say lets do it on mileage covered but old cars are so easy to clock, so that won't work.
Sorry but i don't agree as the vast majority of owners of older cars & bikes are very concerned about vehicle roadworthiness and as drivers of them would drive well within the limitations of their P&J. So i hear you say it only takes one from the vast number to get it wrong, but nothing is ever 100% or we would not have any motoring accidents.
IMHO anything that promotes "historic" motoring activity will enhance all of our lives. NB the waves and smiles we all get?