In an anonymous forum, it is likely that in discussions like this one on the MPL concept, for there to be a number of folks with undeclared vested interests who might well manipulate and cloud the real underlying issues, to their advantage.
Let's face the facts; the MPL concept has been driven by airlines who are becoming desperately short of pilots and want to reduce training and wage costs. The MPL will legally allow them to put warm bodies in cockpit seats in a much reduced timescale at a much reduced cost, and will allow the selection of warm bodies that would not otherwise qualify to be professional pilots.
Safety in aviation is a legacy born of bitter experience that has shaped the selection, training, experience, performance, discipline and punishment systems and processes over many years.
Experience gained through the early years of a pilot's career is very efficient in weeding out most unsuitable pilots by either killing them in aviation accidents, or preventing them from further advancement by denying them further aviation jobs due to poor performance.
To dump these systems and processes based on a century of aviation experience and replace them instead with a new system driven by political expediency and economics is ill-advised to say the least.
If I have discovered one thing about aviation over many years, is that it sometimes lets you get away with taking shortcuts for indeterminite periods.
However, in the long run, aviation is unrelenting and merciless in punishing all folk who are prone to taking shortcuts, along with the innocent travelling public who may be in their care.