Yeah if a third trilogy was made I think the Thrawn series would be great. Thats also where Mara Jade first appears. Shes quite an important character as far as Luke is concerned. Or do the New Jedi Order series. Maybe combine the two and see Leia and Hans kids born and grow up and Luke and Mara meet and eventually get married. Great stuff yes. But it wont happen. Not with GL anyway. He may make a permanent Lucasfilm contract to never make another SW movie even after hes gone. Or if not his kids may create a whole new SW generation of movies.
May the Force be with you...