It is baffling - because 22-28 year olds tend to IMPROVE because that's what learning is. To look at the sample size here and just say "yep, he is what he is" makes as much sense as doing that about his high school numbers. The idea was because he was improving over his tour in Detroit, and that he is just 26, and that he was leaving a horrible defense, that he would be more productive.
Miley has been a little less baffling although given his 3.8 ERA in a launching pad in the NL, you'd have expected his numbers to go up in the AL but not to the degree. Kelly has been inconsistent and Buchholz has largely been solid.