I agree with you to an extent. Yes the Postseason especially a short series like the WC and DS can be random.
Though the Blue Jays never really showed us anything over 162 games other than their dominant rotation, bullpen and fielding. The lineup over 162 was as frustrating to watch as ever. It's not like the Jays bats just went cold in their series against the Twins. They pretty much were awful since the end of April.
Arizona actually was leading the NL West for a certain amount of time, I believe even in June. As well, they have a young exciting core led by Carroll who could be a difference maker in a short series and two solid arms in Gallen and Kelly. They definitely were meant for a short series. Additionally, they ran into a Brewers team that was without Woodruff in that WC series and also a Dodgers rotation that wasn't 100% healthy.
I would still rather the Jays produce regular seasons like the Dodgers or Braves on a consistent basis, rather than be a borderline WC team during the regular season. But regardless, will take a WS anyway we can get one.