Getting a log-book signed by an offical, more red tape, more money for sailing schools (who must pay the RYA), not, I feel one of your better ideas. Indeed it smacks a little of empire building.
Is there any real evidence of candidates faking thier logs?
Can't the examiners tell if they are up to the standard?
In any event there is currently no check on the quality of the mileage, so to use your own argument, milage is pretty irrelevant anyway.