Wow, 9 pages. Must be a hot button issue.
It's not that one cannot learn to physically operate an RJ with very little total flight time - the airplanes are *****cats (as long as you stroke the fur in the right direction!). Motor skills are not the issue.
Decision making is the issue. Learning those skills is a process of 1) You have a job to do...the boxes or whatever have to get to their destination. Everyday. The Boss wants you to go, rain or shine. 2) Making the decisions about how much weight, how much fuel, how bad the weather, when you can go and when you'd be a fool to do so. All eyes are on you to balance operational commitment vs. safety. A remark was made about a 777 Capt not flying a Navajo because of his "good judgement". The 777 Captains I know have spent a lengthy career making decisions about how to practically extract the most utility from every machine they've been tasked to fly - Navajos are flown in bad weather every day. The pilots who fly them live, learn or die by the decisions they make. 300hr pilots hired to right seat of a RJ have cheated themselves of this vital apprenticeship.