Well, that'* really what leather does as it ages. If the surface coloring has cracked off, leaving a dark colored crack on a light colored seat, go to your local shoe repair shop and ask them about leather color sprays for shoes. Test it for color against your seat. I used "taupe" on my 92 seat when I replaced the torn outside bolster last summer with a piece of yellow leather from a buick in a junkyard. I sprayed the yellow piece twice and let it dry, then sewed it in.
It is better to spray a whole piece because the spray has a little different sheen than the original leather. This helped hide some scratches on my seats, but they don't look as good as new - cause they are 14 years old!
If the cracks really bug you, you can get some newer seats from a junkyard.