I agree Eggs, although I think it's part of a youngsters development that they spend at least 6 months out in open age football when they are around 17/19. It's important that they are exposed to the rigours and competitiveness of first team football to test them if nothing else.
Yes, if they are good enough, they probably don't need to spend a season at championship level, but only if they are getting fairly regular playing time in the premier, like with Davies when he first came in. But I still think that testing at league 1/2 level earlier in their career is vital.