We seem to have dropped into hand flying Vs automatics, but the original thread was about low experience pilots flying modern complex jets.
More experience means you have seen more things, including unusual things. Flying C152s solo for several hundred hours and then basic turbo props for several thousand hours; there was the opportunity to consolidate hand flying skills and experience the real world and scare ourselves, and this helped us realise why instructors told to us do things in certain ways.
On an Airbus if you correctly follow Airbus SOPs, (and make appropriate considerations about weather and fuel etc) *, you cannot go very far wrong, and can conduct a safe flight quite easily. So a 140 hr cadet can in theory fly an Airbus safely - assuming they have successfully passed the type rating. I mean, we all passed our driving test and went out onto the motorway, travelling at 70mph only a few feet away from other traffic - a potentially far more dangerous environment - with much much less than 140hrs driving experience.
When things go wrong or non-normal however, that is when experience or lack of it becomes an issue. And in medium and big transport jets in four dimensions, as we know; things can go wrong very rapidly.
When TCAS first came in, there were a number of incidents of pilots who clearly panicked and hauled back on their yokes or dived down to avoid the "impending crash", or ignored or went opposite to the TCAS command, rather than calmly following the IVSI band, making a small adjustment to their V/S to avoid the other 'plane.
And we all know about AF447.
We had a GEN 1 go intermittent at FL350, and it was on/off/on/off, as quick as it takes to read that. ECAM could not keep up and the cockpit was like a Christmas tree of flashing lights, and audible warnings, (and the engine sounded like it was back-firing with the changes of loading on its gearbox). But although it seemed as if the world was about to end, we knew it was not a major issue - we were still airborne and in (manual) control. Madrid was just down there, so we could land quickly if we had to. But CRM, calm DODAR style diagnostics (and a lucky spot by me), sorted the problem out.
There will never be two 140 hour pilots on the flight deck together, but the the real question is whether it is sensible to have a 140 hr F/O with a weak P1C, or in the event of P1C incapacitation. Short-haul over western Europe gives many airports to autoland at and very good ATC, but long-haul in some areas and over the Ocean doesn't.
In an ideal world, cadets would have much more than 140 hrs before getting anywhere near a jet transport flight-deck.
* but this only comes with experience of course..........