Take this with a grain of salt, but it certainly appears to me that the changes to the strike zone that we saw last year have disappeared. I watched a ridiculous amount of baseball in the first week of the season, and I routinely saw the pitch between the belt and the letters–a strike by rule–called a ball.
It gets worse for pitchers: from what I can tell, the horizontal zone is being called correctly, without the wide outside corner that had become prevalent two years ago. This leaves an effective strike zone the size of Bud Selig's credibility, and a near-impossible job for any pitcher with the control of a mere mortal. It was a tiny strike zone that contributed to the bad first starts of Pedro Martinez and Roger Clemens, and led to anomalies like a three-walk start by Brad Radke.
A look at the first week's numbers shows us the change:
2001 BB/9: 3.00
2001 K/9: 6.74
2002 BB/9: 3.50
2002 K/9: 6.61
(Unintentional walks only)
Walks are up, strikeouts are down. These changes haven't shown up on the scoreboard yet, however.
2001 R/9: 4.82
2002 R/9: 4.38
It's just one week, so remember that means the game's best pitchers are overrepresented in this data (for example, Curt Schilling and Randy Johnson have thrown 60% of the Diamondbacks' innings so far). No games have been played at Coors Field yet, while a bunch of been played in cold weather. The biases in the small sample should work against higher offense.
I don't want to make too big a deal about this, but the shrinking strike zone is one of the biggest factors in the offensive explosion of the last ten years, along with better hitting environments and stronger hitters. It's also the one that should be the easiest to address: just call the damn zone properly. MLB made a big deal about this last year, but like so many other MLB initiatives, it's gone by the wayside, leaving us with a smaller strike zone than ever before.
It's increasingly clear that major-league umpires aren't going to call the rulebook strike zone. Until they do, cries for an automated ball-strike system will get louder.