Every year we grouse about the "valuable" prospects we trade away, lose via rule 5 draft, or DFA... yet most of the time, those players end up being fringe MLB players at best.
I'd love to see a summary of players lost by Arnold that actually made MLB rosters and their WAR. There have been a few (Olson, Fry) that end up giving positive MLB impact to their next team, but so many of our prospects rated 10+ get a cup of coffee at the MLB level or never make it at all. I remember people complaining about giving away David Hamilton to get out of JBJ's contract...now here we have him back and trying to replace him (as a starter, he is ok as a utility guy).
Maybe one of Ragsdale or Frias becomes a good/great MLB player, but the odds are against it.