My quick take on the Kouzmanoff trade is that the Padres had to find out what Chase Headley could do and the best way to do it was by trading Kouz. Now Headley gets to play where he belongs. As a bonus, both Will Venable and Kyle Blanks get regular at-bats, which also needed to happen.
It's not like the Padres had much trade leverage. They'd shopped Kouz for two years. He's a solid player, but his trade value never matched his fan appeal.
On a personal note, Kouz gets an "A" for what he accomplished in San Diego despite never developing the plate discipline that would've made him more productive. When the Indians traded him, they doubted Kouz's back would hold up. The condition is chronic. But despite the wear and tear of fielding grounders and the torque of swinging a bat, Kouz kept himself in fantastic shape and stayed in the lineup. His toughness was also evident in how he survived so many plunkings. Kouz's swing invites pitchers to pound him inside more than most hitters. As a result, he got hit by a lot of fastballs and constantly was jammed by pitches. No fun, but he hung in there. He also proved wrong the scouts who said he'd be a liability at third base. Working nearly year-round on his defense, Kouz turned himself into a solid defender. He had an apt mentor in Padres infield coach Glenn Hoffman, a former major league shortstop.