As an aside, in the USA, ALPA backed the FAA 1500 hour rule and has strongly opposed subsequent attempts to remove it, so there are obviously industrial considerations at play.
Its a very good rule for any pilot wishing to fly in the USA. It means that airlines can not apply absolute control the supply of pilots through cadet programs and they have to play the market to hire. As for safety benefit, not as much as it might seem, as the 1500 hour pilot that has not been through a training and checking program can be just as hit and miss on skill as the 200 hour one, just with an experience bucket that could help them. The real safety benefit would come more from seeing value in retaining experienced pilots through better terms and conditions, leading to long term employment and better on the job knowledge. This being realized through a tighter workforce market and the need to hold on to pilots rather than the old 'tap and drain' system.
Having flown with airlines prior to MCC and after, I've seen a general decline in standards in Australia. So if the MCC was supposed to help things, no it hasn't, though it isn't the direct cause of the decline either, more to do with training standards and experience in GA. Did I see an improvement in multi-crew cockpit management practices, nope, pretty much the same before and after and the attitude of the Captain still set the tone for the operation with all the variations of personality involved. Some airlines just shifted fancy words around, like PM vs PNF, and so on. Still saw the same errors and mistakes, regardless of what you called each crew member. So fancy words don't suddenly make you realize what you should be doing if you are not, but it makes the idiots who write these things feel good to see a Shakespeare play in action in the cockpit, even the tragedy part when it goes awry. And before the boffins turn ape, I'm talking the waffle introduced in the last 20 or so years, not the valuable stuff learned back when KLM rammed Pan Am, and similar lessons from the past.