There are two main differences between Janish and Cozart. Janish had better plate discipline and Cozart has a lot more power. The issue with Janish is that he just had a weak bat for the most part (he has had 3 months of at least 50 at bats with an .800 OPS or better in 4 years in the minors). The question with Cozart is can he learn a little more plate discipline? Thats really the only weakness in his game currently.