Dash&Thump;
Certainly one key factor is the selection process. That is where flight safety begins as does industrial peace, I might add. If I might offer a nuance to the overall discussion without appearing or intending the impression of being a big-jet-jockey-self-important-elitist
, (truly laughing, here), I think the environment you're describing is ideal for MPL candidates and agree with you that low-time by itself is not a high-risk factor when other qualities such as intelligence, (native ability though that is not needed in great quantities), and a balanced ego which exhibits a keeness bordering on an unbridled passion for learning are present to some degree.
In short, immediate exposure to, and responsibility for heavy, long-haul operations in which demanding duty-days and regularly irregular ops are "standard", wouldn't be the ideal environment - I hope you take this the way it is intended!
I'm sure we both know that with such candidates, a short MPL introduction followed by a substantive line indoctrination program with a robust checking process can be successful.