We can safely say, based on the 2019 team's record, that Klentak could have made no moves or some very different moves and still had an 82-win team (if we even are one). But I don't know that we can yet say Alfaro and Crawford would have been the long-term answer, any more than Franco, Altherr, Herrera and Williams have been. We also don't know how Santana would have done if he'd stayed here (I assume well, if not necessarily as well as he's doing in Cleveland). But in hindsight would have been okay to take another year to find out all those things.
I almost think you have to split Klentak's off-season into before Machado/after Machado. If he really knew it was going to be Harper would he have considered keeping Santana for the 3B experiment? And what if Machado had insisted on playing SS after all? (There was talk of moving to Segura to 2B and trading Cesar if so). Whereas it seems like by the time they got Realmuto Harper was their guy, though it was still a couple of weeks before (certainly if they'd wanted Manny they could have easily beat the Padres offer though)
It's all hindsight but I don't think there's any question they'd be better off right now if they hadn't made all of these moves. We are in a window that's closing fast on Segura, Cesar, McCutchen, Arrieta and Robertson (on whom it is already slammed shut), as well as Realmuto in theory (if he leaves, or if he's not nearly the offensive player he is after 2021).
And now they have to make the same decisions about CF, 3B and 2B. If the goal is to win big in 2020 Haseley, Kingery and Hernandez aren't (collectively) the answer and I'm not sure simply moving Kingery to 2B and acquiring a 3B is enough either. Haseley as a 4th OF who may be a cornerstone player from 2021 on? Yes. But he's also a trade asset.
Lauber's write-up of Corbin was pretty convincing to me too.
Arrieta’s contract was shorter, but his average annual value is higher than Corbin’s. The Phillies are paying Arrieta a premium price ($25 million per year) for his age 32, 33, and 34 seasons. The Nationals are paying Corbin $23.3 million for his age 29-34 seasons.
The first half of Corbin’s contract will likely cover his prime years as one of baseball’s elite left-handers. The second half could include his regression. For the Nationals, that’s fine. They’re paying for what they get in the first three years, not the last three.