No I wouldn't feel overly comfortable if it was me with the 250hrs and 737 strapped to my backside actually. On my second Revenue Earning Flight we're in the stack above the busiest airport in the world in a steam driven 737. The wind is gusting 40 knots across the runway, the a/c is fully loaded and we haven't exactly got tonnes of fuel to spare. Suddenly the old guy next to me clutches his chest, turns purple and slumps in his seat. Go.
Could I handle that with 250 hrs ? My first EVER real airborne emergency. No instructor available, everything happening quickly and the adrenalin pumping... No I don't think I could handle it well enough to leave safe margins for the 100 odd poor souls strapped in with me. You have to visualise (as with all aviaition safety matters) the worst scenario and plan for that. The weakest Cadet from the course with the least experience suffering the most serious of incidents at the worst time. It'll probably never happen but all aviation accidents probably wouldn't happen but they still do and are still planned for in SOP's and aircraft/engine design.
But this was not my original intended point. There are plenty of very hot ex 509 Cadets who make superb pilots from the start. The biggest issue is actually the extra workload that flying with a Cadet generates for the Captains. They just don't like it too much and who can blame them? Also what will happen in a few years time if the airlines take too many Cadets - you'll have a 1,501hr Captain and a 250hr Cadet flying out of major hubs in hefty metal like a 757! Just doesn't look quite right to me - wonder what Joe public will think as he sniffs a faint whiff of acne cream and sees both his pilots walking up the aisle neither of whom are over 29... Will he feel reassured and glad he chose this airline rather than the last one he flew with which had two firm jawed, grey haired veterans at the controls who were much closer to his age and background.
As with all things, balance and diversity is the key. BTW, grey hair is more of a problem for me than acne ever was! WWW