I think sun bears and possibly a rhino species could be exhibited at London again but it’s a question of how much space they’re prepared to use. Truth is the zoo has lost one of its lawns for the reptile house and I suspect they’ll be reluctant to lose anymore.
I would love to see Sun Bears replace the wallabies and emus in front of the Mappins. Not only a homage to the days of bears on the terraces, but it could combine with the tigers, babirusa, gibbons and Komodos to create a Southeast Asian zone of sorts. Space isn't an issue, with the combined area of all the wallaby and emu enclosures is 1,300 square metres, which is more than enough space for Sun Bears, the smallest of all bear species - for reference, the outdoor portion of the sun bear enclosure at Colchester, which so many, including myself, consider to be a world-class enclosure, is just under 900 square metres. I can't see rhinos returning as I don't see where they would have the space, and the claims made by some others on this forum that there is enough space to bring them back to the Cassons seem a little far-fetched and fantastical to me.
The area of land at the zoo that feels most underused is the canalside. The zoo has plenty of space on either bank of the Regent's Canal that is, barring the hunting dog and warthog enclosures, entirely underused. Said hunting dog and warthog enclosures are perfectly adequate, and both of which are located at the narrowest point of the land between the pathway and the canal (varying between 7 and 12 metres), while the areas on the North Bank (either side of Snowdon Aviary) are upwards of 21 metres wide and sloping, so, while nothing comparable to rhinos and bears, they could easily house something interesting. Personally, I would love to see cassowaries on the North Bank, which would extend a long tradition of keeping birds in that area (of course there are the recently closed, and hopefully soon-to-be reopened, owleries and pheasantries, but at one point there were also paddocks for pinioned cranes and geese here), and wolves on the South Bank, taking advantage of the woodland-like foliage, and with the canalside having already proven itself adequate for canines with the hunting dogs. The wolves would replace the Woodland Walk, which is lovely, but feels a bit redundant given that the zoo is located within Regent's Park, which offers more than enough of interest for visitors to look for wildlife before or after their visit to the zoo.
Regarding the Reptile House, I am beyond excited and have a visit planned for opening day on Good Friday, and although I may be forced to reschedule, it is looking more and more likely by the minute. In the hope of having an entirely unbiased first viewing of SLoRA, I have refrained from reading any of the reviews generously shared by members who attended one of the Fellow's previews upthread, with the same applying for any images on the gallery. Hopefully all goes according to plan and I will be able to share my own thoughts in a few days time!