I agree Mark
A famous exhibit such as this should i think hold something like a Big Cat or Bears like it has previousley.it could've made a splendid Lion Enclosure...Lions would opf looked great in there and it would be fantastic if one of the 4 large Rocks could of been open to them to look across the zoo think of them as Kopje's
For its age being built in the early 1900's it was a complete break through in English Modern Zoo Architecture and was modelled on Hagenbecks brand new Enclosure Designs.
Trying to make good use of it however is tricky and as ive said before i dont think Wallaby's quite suite the Mappin Terraces!
It is a very disappointing use of space but it still is one of the best wallaby enclosures I've ever seen. I think what makes the whole project seem more wasteful is the fact that it's actually a good exhibit, but the space could have been used so much better.
When this first happened I had hoped it was an experiment to see if the Mappin would work like this. Perhaps, trying this format with an unimportant and available species that can test whether the enclosure is unescapable, workable from a public and staff point of view and that simply acts as a filler until something else was viable. I hoped that this was a test, and a stop gap for much bigger and better things (like lions).
Sadly I'm not sure now. I still hope, but the decision to plant Eucalyptus and other Aussie trees suggests that this may be a longer term solution than I'd wanted.
My personal view is that in a small zoo like London this large plot of land needs a 'big' species. I think a big cat would be a great solution, the space'd be about right, the viewing is fairly good and to be honest, the current cat area is a little dated, so the move would free up space there. The problems may be that there is insufficient indoor space (though there was clearly enough for the sloth bears?) and cats may be able to climb out as it currently stands.