I think over expectations have colored the evaluation of Klentak:
1) He did improve the lineup, imagine this team with Crawford at SS, Alfaro at C, Hoskins in LF and Santana at 1B. Uh, butt ugly? Maybe Santana at 3B and Hoskins at 1B? Still not pretty, would Santana hit NL pitching like he hit AL pitching?
2) The only pitcher out there was Corbin, but if you're going all in on Harper, it's hard to go all in on Corbin with the Nats willing to pay (and probably more to keep him from the Phillies) - we'll see how long he holds up, we knew he'd have a couple good seasons, but 6 years is a long time for a pitcher.
3) Klentak had no inkling that Arrieta was going to break down this year, the 3 year contract was smart (some here wanted to give him a Corbin contract). Nola, Arrieta as your one/two allows you to go with three young starters, Eickhoff returning and a deep AAA staff. Crap happens.
4) Even with Harper, Vegas had this team at 82-88 wins (two different books), which dictated against giving up significant assets to garner another couple wins. It was one thing to make short-term moves after 2008 to keep the window open, quite another to do so when the window was just opening.
5) His mid-season moves were fine, he kept them in contention without giving up any significant assets.He'll have some money to spend this offseason, and all his best prospects - he just needs more of them.
Was it a great job? No. An unmitigated disaster? No. More like treading water, trying to build a presentable team while continuing to rebuild. The real key to his regime will be whether the organization as a whole enters the 21st century, and the "purge" of dinosaurs will make or break his legacy - this team needs better scouting and player development, and all the free agents they can buy won't be enough if they don't consistently develop fresh talent.