Campbell was a very polarizing prospect. There were many who believed his swing had a huge hole in it, and while he breezed through the minors it would be exposed at the MLB level.
In hindsight, really feels like maybe they should have seen how it looked first.
Also, if they were going to completely recreate his swing, maybe they should have demoted him a few levels and face off against worse pitching. If you're going to completely rebuild someone, do it from the beginning.