Jason Parks has published his top 10 Cubs prospects list with scouting reports and it's fairly impressive. I'll only quote Baez's future potential since it's a subscription site.
Baez might lack Buxton’s overall athleticism or Bogaerts’ polish, but the 21-year-old Puerto Rican might have the highest offensive ceiling of any player in the minors, a potential middle-of-the-order force capable of hitting for average and obnoxious game power. While he’s no longer a true boom-or-bust prospect, Baez carries more risk than the average high-end prospect with Double-A experience because of the extreme projections on his tools and the balls-to-the-wall approach he often brings to all sides of the game. As Baez matures and adds more patience at the plate and more confidence in the field, he should develop into one of the game’s elite players, a left-side infielder (short or third) with an offensive attack that some scouts project to achieve Miguel Cabrera-level heights, an extreme comparison but one that his elite bat speed and power potential could make a reality if everything clicks.
Parks has mentioned the Miguel Cabrera comp a few times and it doesn't make a lot of sense to me. In the minors, Cabrera struck out much less frequently and walked more than Baez did. To be fair, Baez showed more power, so the comp is only legitimate if you expect Baez to cut down on the strikeouts and walk more. I'm not sure I do. I think a big part of the reason he has so much power is he goes all out on his swing and cutting down on that will hurt his power. We should see Baez at some point in 2014.