I agree, I love saddles like this: broken in and comfy! Why do you want to sell it? Doesn't fit your horse anymore?
It does need to be reflocked. A knowledgeable buyer is going to mentally tack 100-200 dollars (some people are charging even more now) on to your price for that. Stitching is pretty negligible, but the state of the stuffing would make me think twice. To me, this would be an acceptable level of leather wear. If anything, the way it has worn tells me that the leather is of decent quality.
Reflocking and replacing the knee roll could really make this like a new saddle for you at a fraction of the cost of buying another.