6/6: You asked who exceeded expectations. Mantha and Athansiou both did. Mantha is either the 2nd or 3rd best 20th overall pick in the last 20 years. Definitely behind Brent Burns and maybe Travis Zajac. Athanasiou was/is a regular, contributing, top 9 NHL forward despite being drafted in the 4th round. Neither are superstars, but both of them (like Jensen) turned out just about as good as one could expect given where they were drafted.
So again, if Blash bears responsibility for guys like Mrazek, Sheahan, and Svech not panning out then he MORE than makes up for it by getting more out of the guys I mentioned than could reasonably be expected.
OR (and this is my position) he really doesn't have much to do with guys Svech's failures or Jensen's successes. The first lost almost two full years of developmental time to serious injuries and probably still isn't NHL caliber, and the second plied his trade in the AHL until he was 26 before he was finally NHL ready and only then did he get called up and used in a depth role he could handle.
One final thought: The Red Wings drafting and player development was absolutely abysmal under Holland. The ONLY top six forwards drafted and developed between Datsyuk/Zetterberg and Larkin/Mantha were Tatar and Nyquist (maybe Filppula or Hudler if you're being REALLY generous). So from 1999 to 2013 they drafted 2 top six talents. The ONLY top four defenseman they drafted and developed between Kronwall and Hronek? None. Not one. From 2000 to 2016 they developed ZERO top four defensemen. This was a systemic problem that had a lot to do with A) bad draft position, B) piss poor decisions by the GM on draft day, and C) a terrible development program and almost nothing to do with Blashill.