Minimum hours
What a load of tosh, typical kneejerk reaction!
It is good training and subsequent supervision that keeps low houred co-pilots safe, not 1500hrs experience.
In BA we put Flying College trained pilots onto the B757/767 with around 250hours total experience with no problems. They had restrictions for sometime that meant they only flew with experienced Capts.
These pilots now make up a large proportion of the Capts in BA.