Blumbergh,
You're assuming that you can correctly evaluate a player to have a 10% chance of being a top 5 player at any position, but you can't. You can draft a Jon Lester and Michael Bowden, both of whom coming out of high school were very similar and see neither make it past lowA. The spaghetti on the wall analogy is a little overused because a team with good scouts can decrease their attrition rate from something like 98% to 93%, but the analogy is still appropriate. For every Jon Lester you get 100 Kris Johnsons, and for every Dustin Pedroia you get 200 Jeff Natales.
Of course every team tries to hedge their bets and draft as many superstar potential players as possible, but for every single one of these players there's no guarantee that they'll amount to anything.
I hate to continue this argument, but you keep bringing up replacing Michael Bowden with Dustin Richardson. I get it, you're saying that one guy is replaceable with the other, but they're both from the same system with the same skillset for the same low cost. That's actually valuable, a GM doesn't need to trade or sign a guy who will cost more yet yeild the same or less production.
To save a little frustration on everyone's part, would you please rank your top 10 or 15 so that we understand just how much you value each of these high ceiling prospects. I'm expecting to see guys like Renfroe, Britton, Middlebrooks, Almanzar, Tejeda, et al ahead of the higher floor/lower ceiling guys like Richardson and Bowden.