Back in my day, you used to be able to find interesting and useful players in the Rule V draft. The best one the Reds ever did was when they got Josh Hamilton before the 2007 season. He went on to make five All-Star Teams and won an MVP (the same year Joey won his!). Johan Santana, Joakim Soria, Shane Victorino, and Dan Uggla were all taken in the Rule V draft before making it solid in the bigs.
Maybe I’m relying too much on my gin-addled memory and not doing even cursory research to find out, but it seems to me that we haven’t seen a real star make the big leagues via the Rule V in quite a while.