>>there is every chance 'tweeking' the rules will make the problem a whole lot worse.<<
Well not really; The amendments seek to close a loophole which the CAA never imagined any operator would seek to exploit in the first case. Scientific research has illuminated a problem which many of us had already been concerned about.
>>The CAA, as the regulator, needs to learn that regulation should be a last resort.<<
I too would hope that regulation is a last resort in preventing fatigue in airline pilots. However, airlines use CAP 371 as a work target so the regulation needs to reflect that limits are used as a day to day working practices.