I can think of one accident where a large aircraft was destroyed by flying it like a little aeroplane (Queens), several where good handling skill from little aeroplanes saved the day (Hudson, Gimli) and at least one where better basic stick and rudder skills would probably have saved the day (AF447). I can also think of a larger aeroplane pilot who destroyed a smaller aeroplane and killed himself because he didn't understand the differences, and a second just the aircraft (both known to me, prefer not to declare source)
So, that seems to put things in favour of little aeroplane training, but that big/little aeroplane differences ALSO need to be carefully trained into big aeroplane pilots.
G