An important question is why do so many of the zoos newer exhibits need improvements so soon after being built. The answer to which is unlike many zoos the zoo is not building with a good level of foresight. Also do these changes have much if any impact on welfare?
I think a lot of the argument regarding this zoo on this site was premised around the fact that this more than other zoos is a zoo built for visitors, where animal welfare often is deprioritized. Expanding a giraffe deck does nothing for its inhabitants. Fiona's exhibit looks amazing for visitors, there is no debate but it was inadequate the day it was built and could have been doubled in size if not for crowd pleasing meerkats and a playground. The classic example is the cat house. The zoo was basically like you know if we turn the lights off people won't realize how bad the exhibits are for the cats.
Also if the giraffes move to elephant house one could simply expand what area is "Africa." Its arbitrary anyways but it is next to the existing complex. Zoogeographic theming is fine but we can't let it stand in the way of basic welfare.