Full explanation
here, last year's thread.
Inside-the-park homers don't work right in OOTP, outside of a modern MLB setup with modern MLB parks and style of play. If you're trying to sim the deadball era, or a fictional era with huge ballparks the frequency of ISTP homers is way, way, way off. Lots of deadball era players had 30, 40 even 50% of their homers inside the park. In OOTP, no matter the size of the park or the era you play ISTP homers are hard-coded as a tiny fraction of overall homers.
So, if you have Jesse Burkett playing in a park with a couple 500-ft walls and accurate overall park factors he'll hit roughly six homers a year, like in real life. But if you follow along the play-by-play, chances are very good that every one of the homers will be over the fence, some probably 500+ feet, when in real life half of them were inside the park, and he probably never hit a soggy, stained, deadball era ball 425 feet in his life.
And yes, this is a largely cosmetic fix. Like I said, Burkett will hit the right number of homers. But the play-by-play text will be all wrong, and if we get that OOTP13 2D/3D engine the on-field action will be all wrong.