To be fair, they ran into 4 good teams in their 4 playoff trips with Harper, and they were very close losses (3 of them going the full 5 games, and the other was 3-1 to the eventual champ Giants in 2014, featuring 3 one run losses -- the Nats and Giants actually tied at 9 runs for the series!) And they didn't have Strasburg or Rendon for the first one of those, or Scherzer for the first two, so there are more key differences than just Harper.
They certainly are playing well this year, though! And to think, they not only started the year 19-31, they've also been on the brink of playoff elimination twice -- trailed the wild card game by 2 runs with only 4 outs to go, and game 5 of the NLDS by 2 runs with 6 outs to go.
This all sounds like they really want to win!
I've actually been pretty impressed with how all the teams have played, with one exception. And when I see how the teams have played I think to myself how the Twins were just not that good. And before anyone says 'It's the pitching, it's the pitching', well, yes, but that's just part of it. How the teams have played is the difference.