The Braves did OK during the Wren/Manno/Demacio drafts if you grade the drafts by the amount of players that can get to the AAA level. The problem is, they drafted very few legitimate major league prospects who are high level, impact players. Evan Gattis is a nice story, but he's probably going to be traded this offseason to an AL team where he can DH. Alex Wood was a great pick. Lucas Sims is a high level prospect. So, they have essentially drafted two high level prospects prior to this past year. Frank Wren and company inherited a system that already had Jason Heyward, Freddie Freeman, and Julio Teheran, and Craig Kimbrel and Mike Minor was drafted during the Roy Clark years.
Here's the Braves problem with the Demacio drafts. They played it safe. They went after college guys with limited upside to build depth in the system, but outside of Alex Wood, that group of college guys has not produced a high level prospect.
Under Roy, the Braves routinely had high level, impact prospects. Whether it was Adam Wainwright, Brian McCann, Jarrod Saltalamacchia, Elvis Andrus, Jason Heyward, Freddie Freeman, or high level prospects that didn't pan out at the major league level such as Jeff Francouer or Andy Marte.