FanGraphs has posted their list of the Pirates’ top 35 prospects. It’s actually much more extensive than that, as it includes capsule comments on a number of other players, including some of the international prospects the Pirates just signed. The scouting reports on the top 35 are detailed and well worth a read, partly because the authors, Eric Longenhagen and Kiley McDaniel, at least in my opinion are the gold standard for online prospect writing.
Overall, they refer to the system as having “sneaky upside,” which is a product of a lot of the hitters being in the process of trying to alter their approaches.