Chamberlain did not have control problems in the minors. He didn't have control problems before this season really. This season he's hit 10 batters. And even given all that he's been an average starter
Fangraphs had the CC deal as even for both sides. They had the Cards deal as the Cards giving up $25m to get $8m in value. That was just for Wallace, before other players were added.
The fact that you say Melvin didn't bring in any prospects doesn't make it true. He did. He got Jorge De La Rosa, Zach Jackson, Jose Capellan, and Carlos Villaneuva. Capuano had all of 33 innings in Arizona before becoming a Brewers.
Hart over the last month .286/.390/.357. Is that great? No, but is avergeg given its so OBP dominant. Turn a few doubles into home runs and it would be great.