Most of the game's control mechanics have been retooled and work much better, including using the SIXAXIS' motion control to slide into bases, which was a cool feature last year that didn't work well enough to warrant using it. Sliding is actually one of the game's deeper functions since you can use the analog sticks to execute any number of slides, such as hook slides, depending on the current situation.
The relationship between the pitcher and batter is one of the core focuses in MLB 08: The Show. By hitting (Select), you can now bring up a tool that indicates which type of pitch a batter is more successful hitting or what types of throws a pitcher favors. You can also bring up a menu that highlights what type of pitches a player has in his arsenal and which have the higher strike percentages. When looking at a batter, you can pull up info that will help a pitcher get a better idea about how to handle the guy at the plate. You're not obligated to use the provided info, but it helps a lot - especially when dealing with players you aren't familiar with (which, for me is anyone not associated with the Oakland A's or a former LSU player).
Another new feature is the Progressive Batting Performance system, which tracks how hot or cold a batter is. The system is represented on-screen by icons that show how confident your batter is at the plate. The PBP system is a pretty useful device for determining your player's state of mind as well.
Batting and pitching aren't the only areas to receive spiffy new upgrades. Fielding has received a few cosmetic updates like additional animations and pitchers will get in front of the ball if it is coming their way rather than letting the fielders handle it.... well, most of the time anyway. When a ball is going towards the wall, the Rob Home Run system activates by first showing a series of circles on the field that show a rough trajectory for the ball. If you can get your player into the circle, you can snag the ball out of the air with a well-timed button press. It's a great feature and helps address the problem of too many home runs.
MLB 08: The Show doesn't improve on all of MLB 07's shortcomings, but it does more than enough to make up for it. MLB 08: The Show plays just as good as it looks and should find its way into every baseball fan's collection, even if you have to buy a PS3 to play it.