I went to SFKK before I had to catch my plane back to Detroit last fall in 2007 (after a trip to Holiday World of course) and I thought it was O.K. It had some nice decor and landscaping in the front of the park, the original part of the park with the Superman ride. The nasty bridge across the access road and the back half of the park was not overly impressive though unless the theme idea was supposed to be very industrial. I don't know if I'd go back again but it wouldn't be because of looks, but rather the lack of fun stuff to ride other than Greezed Lightning, Chang, and Deluge.
I wouldn't sell the park at all though if I was Six Flags with it being so close to the airport, the University of Louisville, Churchill Downs, Freedom Hall, and the Kentucky State Fairgrounds. Too many opportunities for impulse visits I would think.