The concern with Winker is that he is a poor athlete as a teenager. Imagine what his athleticism will be like if he puts on a bunch of weight as he gets older or develops some nagging injuries. Right now, his glove projects as 'adequate' to 'passable'. If he porks up or loses a step to injury, OF might not even be an option for him anymore. He might be relegated to 1B.
Guys like Choo, Ludwick and even Dunn were fantastic athletes as teenagers. Choo and Ludwick were both plus defenders in the major leagues when they were in their 20s. The only reason their gloves are mediocre now is that they got old. Winker is likely to arrive in the majors with a mediocre glove, and it will only go downhill from there.