With the likes of Alexandria Zoo and the Tecton buildings at Dudley, I think it's a case of just rearranging the species to get ones that fit the space better, like having red pandas in the old bear pits (something that can utilise the upwards space rather than sit on the floor). Better them than tigers or bears (although I gather the bears they do have are elderly and thus it's not such an issue since they will hardly be bounding about).
Not that it would ever happen (only in a dream world!), but with the interior space here in this Lion House, I'd rehome the lions elsewhere in the zoo, knock their cages (or at least some, say into two, three or four large cages) together, bring them forward more and probably increase their height. I'd then fill them with bird species and/or small marmosets, so you'd have their song and chatter echoing like in a church (an apse of which this building does resemble a little). A sort of "Small Amazon Species House" if you will
Nice and sensible suggestions all of them, I think.
Funny that you should mention "... having red pandas in the old bear pits..." since I actually proposed just that in a comment in the gallery about the former polar bear Tecton enclousure at Dudley...