There's a good chance you are getting the best player in the deal in Ozuna. Guy has Nelson Cruz potential! He had some absolute monster stretches coming up in the Marlins system, like hottest dude in milb for a couple weeks at a time. If he can translate some of that to MLB more consistently you've got yourself a 4-5 hitter.
I don't view Conley as a reliever, but as someone who is ready to step in to a major league rotation. Might even out-pitch Paxton in 2016. They both logged 67IP in 2015 and Conley FIP was a half run better. He was a starter the last couple months and those last 4 starts he was really putting things together. As an extra piece to even out a deal, yes please!
I do firmly grasp your point of getting the best player in the deal. In this instance while Paxton (and Walker) have both been highly touted the M's could pull a fast one and end up with the best player in the deal (or two best even). Since none of the players involved in the talks are super proven at the MLB level it all comes down to who does the best job evaluating young talent and health.