I would suggest the area being redeveloped on the site of the elephant exhibits would be preferable, though it depends how attached they are to a South East Asian theme (Sri Lankan leopards being a South Asian species). Like
@Zorro says, the emphasis is on vertical, not horizontal; so with this in mind, I’d love to see a multilevelled Sri Lankan leopard exhibit.
Even with Sundah’s death, I imagine the zoo will use the space to accomodate a repeat breeding of their snow leopards, potentially retaining up to four cubs into adulthood. They only had one male in the litter last time; but three males could well follow and require seperate housing as they mature.