I love these kinds of speculative threads, but I've been following this one with increasing horror!
The giraffe house is such a picturesque, iconic enclosure; I really hope it is kept as a heritage building even if the inhabitants are moved into the 'savannah' area.
ROTRA and SOTJ can both claim to be the best in Europe. They should be used for their original purpose until they outlive their usefulness. I'm sure ROTRA isn't understocked but why not simply bring in another breeding pair of jaguars, or at least another female, for SOTJ? If you really want to add variety I would accept Pumas and another gibbon species as reasonable additions.
I think the best suggestion so far has been Maguari's reimagining of the Tropical Realm as a temperate Sichuan House, which was nobly embellished by Brum. Perhaps the Red Panda could be moved to here, and Takin and Clouded leopard added in addition to Francois' Langur.
Zia's suggestion of a native wildlife zone at the top of the map also has a lot of merit I think.