It doesn't make organizational sense to fast track prospects, anyways. First of all, for every Bryce Harper that seems to relish continuous challenge, there seems to be many others who lose confidence as they tread water against more advanced prospects. So you run the risk of ruining a kid's confidence by raising the probability they're overmatched, and what's the reward? Maybe getting a kid to the majors a year or two faster and using up their team control years before they're ready to contribute their peak performance?
Let's not turn Goodwin into Jordan Schafer and rush him up just because we need a CF. I think ideally (and the Nats seem to follow this pattern) you let every prospect spend a year at each level, whether it's over the course of one season, or returning them to where they finished the previous season if they were promoted mid-year the season before.