I agree with you Mario, as it makes for a cool experience for zoo visitors. To be inside an old cage is better than seeing a big cat pace back and forth all day long.
I had my lunch in this cool restaurant in 2005, amazing place, because they didn't cleaned the house after they have moved the lions and tigers and before they rebuild the house into a restaurant, so the carnivore smell is still there....Great Experience and the burgers are double that delicous...
Unfortunately, the Leipzig Zoo has not rebuild his old lion house into a restaurant, it is now a boring"Explorer's Ark " ,but Frankfurt Zoo has used one of the outside cages of the old carnivore house for a cafe, until they crashed the house to build the new Cat-Jungle.