That's a good point. As Joe said, it probably was in last year's game, but not properly.
To be honest with you, I spent most of my time batting/fielding in My Player mode as a position player because I wasn't a fan of the super accurate pitching. I did like the AI pitching though, and as far as energy goes, it seemed the AI's starting pitcher's energy would go down by 1 point for every pitch. So after about 100 pitches their stamina was drained, which seemed pretty accurate since
most major league starters can throw around 100 pitches
on a good day. Then relievers and closers would have their stamina drained much faster. It worked pretty well after the patches.
As for the AI pitching and ball/strike ratios, I thought it was great in 2K10. It was not hard at all to work a walk with default slider settings if you show some patience. The AI pitchers threw pretty intelligently depending on the count (For instance, they tend to throw you junk out of the zone if they were ahead of you in the count). 2K really got that aspect of the game right last year, so I'm expecting to see similar results this year.