Intruder pretty much answered my question... To qualify as PIC/Commander of an aircraft of more that 12500lbs/5700kgs MTOW you essentially need to hold a valid ATPL and an appropriate type rating. To qualify for an ATPL you need the theory (of course), minimum 1500 hours, 500 multicrew, some IFR time (if I`m not mistaken) and some PIC time. But those are minimums for the license, not what an airline actually may require for upgrades for F/O to Capt.
A lot of things can be said pro and con the MPL license, and the training. But the one thing I really think not a lot of people pay attention to is the factor called situational awareness. One side of it has to do with aircraft position in regards to distance, altitude, attitude, speed and so on. The other has to do with being able to make a mental picture of what every other aircraft is doing, where they are and which way they are going. I don`t think this can be replicated in a sim, with all kinds of ways of speaking English and accents, though you can of course practise collision avaoidance. My point being that with having a menatl picture of the traffic you should never be in a position where you need to take action because of TCAS activation. The other thing I have against the MPL is that if the Capt suddenly is incapacitated, the MPL is PIC/solo for the first time in his flying career
with around 150 pax on the other side of the cockpit door. With a bit of luck there might be another pilot onboard who can assist with radios and checklists and such, but if not then this is an immense task
