I hate judging umps based on a rulebook strikezone. Judge them based on consistency. If an umpire isn't calling strikes at the top of the zone all night for both sides, there's nothing to complain about. Hitters and pitchers at the major league level will adjust to any consistent strikezone.
The problem is in consistency. If an umpire randomly calls a ball a foot off the plate a strike at a crucial moment, it can change the entire game. Or when an umpire has a wide zone and suddenly shrinks it screwing one team over. Those are the problems.
Fairness should be the goal, not adherence to the rulebook zone.