Yeah, Wade and Heck definitely deserve some credit. I'm not sure they fixed the farm as quickly and as well as they could have, but no one should act like they completely bombed either. Castro, Folty, DeShields, and Springer all look like excellent draft picks, and getting Singleton/Cosart/Santana/Zeid for Pence was undoubtedly an excellent trade.
As for Luhnow's prospect trades, yes, we won't know their ultimate impact for years, but you can certainly evaluate them now based on the players' ceilings and likelihood of fulfilling it. Unexpected injuries may happen, or players that you gave up may end up far exceeding any reasonable expectations (ie., Chris Johnson this year, or Ruggiano last year), but that does not mean they were stupid trades to make. It's all about risk and probability.