Berrios is on the edge of qualifying for the last 10 years which is why I didn't include him, looks like he didn't pitch in the minors in 2016. He was a prospect during the Terry Ryan 2.0 days, but hit his stride in the majors in the Falvine era.
It's not that Ryan wasn't a rankable prospect, it's that he mostly a product of Tampa's farm system and not ours. I don't mean to say that the Twins organization doesn't deserve credit in developing him, just that this process happened almost entirely in the majors and didn't happen in our minor leagues / farm system. And yeah, clearly the Rays didn't value him or Strotman because trading both for Cruz was a huge risk for them, even without hindsight that seemed like a lopsided trade in our favor.
I was referring to how Petty alone was able to get the team two affordable years of Sonny Gray, essentially cashing in a draft pick for a near top-of-the-line starter was one of the best moves Falvey made. Especially seeing the success rate of his pitching prospects, it was a prudent move.
In conclusion, Falvey's pitching staffs in the majors did a good job with what they had. The farm system, however, did not see very many pitching prospects fulfill their "hype" and the Graterol + Petty trades showed that they were better off trading them for MLB players rather than continuing their development. Povich and Hajjar were traded too and while their returns failed, they still commanded a bit of value. Though I should note Povich still may develop into something.