I would like to see a simple graphical rendition as per Football Manager. This would take significantly longer to implement than most other features, so perhaps this is a request for OOTP 12.
It would be great to see the actual dimensions of the ballpark come into play Live onscreen, such as a huge green monster-esque wall. Or a long fly ball caught up in a stiff wind to right field.
This would require a physics based engine, or at least pseudo physics based, much like the old FPS Baseball series. A lot to ask for I know, but it's what I want in a baseball game.