Ok Peter.
I always said, i do not belittle anyone. The RJ guys have done their part, agreed. We've all heard the tales about LCY and what it took to fly it.
Now just how would these RJ jockeys react, if i'd pretend that because i am a heavy jockey, i'd be able to switch seats and fly such approaches like a dream in a RJ80??? .... They always say "...nahhhh, it really takes some training, adaption and experience to be able to wrestle these birds down into the city ......." -- Aha! --
Every operation is different. That's my point: A RJ, even a 73 or 320 skipper is not just born to take a -500 or -300ER seat due to his ability.
IMHO it is bad practice to take DECs who have not flown similar equippment or in similar environement. It is per definition NOT Direct entry.