Neat idea, and one we'll hope will offer some affordability in the storyline/news area in future versions. On the heels of your idea- whether the game incorporates it or done by a third-party utility, I've always wanted a tool that would let me plug in a combination of stat variables over a certain period. For instance, #SB in last 20 games, or BA with RISP for last 10 games, etc... Has to be complicted to code, but what a handy frame of reference.
To Markus' credit, we have a lot of the basic information available in splits, data for the month, last month, playoffs, etc... just be nice to narrow it down and also have a choice of what data it pulls.

Might be room for replacing current tables, too. I'm not sure I've ever actually looked at how one of my players did on grass vs turf.