For the most part, the ABS challenge system is highlighting how good umpires actually are. Like 250 pitches thrown in last night's game, and players felt confident enough to challenge a single call. And only the Kurtz strike 3 really stood out as one that probably should have been challenged.
We as fans see a pitch out of the zone by an inch or two and cry about how bad the ump is, but in reality there aren't many calls in a game bad enough that the players on the field are comfortable challenging them.