I've had good to excellent results applying Proofide (the Brooks company's saddle dressing) to older saddles ( both on top and underneath ). However, they haven't been in quite the same condition as the saddle you have shown in the photographs. I have also used saddle soap with a moistened cloth, worked up some lather and applied that to the saddle surface. This cleans up the saddle and handles some of the abrasions. For abrasions, very light touchups with the tiniest bit of good shoe polish, along with a good buffing with linen cloth also helps to revive the appearance of the saddle.

Sheldon Brown's site suggests neatsfoot oil, even motor oil! He has stated that he obtained good results
from placing the saddle upside down in an oil bath ( oil in a shallow pan, say ) for an hour or so, then wiping it off and letting the leather regain its pliability. You could try any of these methods to see if it improves the condition of your saddle, trying the less extreme methods first.

Best of luck!

Sudevan