What everyone else said. Unless he is SPECTACULAR (like really truly exceptional) then he's not worth keeping as a stud. A good stallion makes a GREAT gelding.
Also, 20 years' experience doesn't automatically make you experienced enough to handle a stallion. My Mum has been riding for nearly 30 years and has worked on breeding farms with stallions and she STILL doesn't own a stallion, and doesn't think she's experienced enough to own one.
Young, uneducated, AND entire is something for professionals ONLY in my opinion. Geld him and get a good coach/trainer to help you, sell him to someone who CAN handle him, but whatever you do, DON'T try to fix it on your own!