I think the team didn't want their top pitching prospects pitching at Las Vegas when those 3 were promoted from AA, but I wasn't following the team as closely back then so I could be mistaken.
Would you feel better if he had kept Happ, Nolin and Graveman? Then again, the team wouldn't have Michael Saunders in LF and Josh Donaldson at 3B.
Also, who are these "bunch of depth guys" you would've added and, if you're referring to guys looking to rebuild their value after a down or injury-filled year, would the RC really be your first choice to rebuild your value?