Agree. A washington manager has won two of the last three years--Davey Johnson won it three seasons ago. Are the Nationals that bad that getting them to the playoffs is a monumental achievement? And what Yost did should be recognized. He didn't receive one first-place vote. Even if the vote is done after regular season, he deserved it just for getting that team to the postseason.
Kind of agree with you on WSH, but KC was supposed to be around .500 if you took a look at the preseason totals. Yes, they finished way over .500, but at the same time like 7 games behind Baltimore, whose total was set at 79, bet up to 81. And Baltimore did all that even though their biggest pitching addition (Ubaldo Jimenez) sucked and they lost two key players on their team for 1/2 the season (Wieters & Machado), while KC stayed healthy pretty much all season. So I wouldn't blame anybody voting for Showalter at the point, when the voting was done. Plus Yost almost got them eliminated in the play-in match vs OAK with the pitching change to Ventura.
But if you only looked at the regular season, I perhaps wouldn't even rate the Royals achievement higher than OAK or LAA, who lost major parts of their team (A's lost 2 of their top4 starters in preseason for the whole year and still made it to 88 wins) and finished with great records.