To give some extra background to this, The sale of land was betweem the previous administration and the RZSS. Unfortunately the council hadn't consulted the neighbours about their plans. the way the media has portrayed things it makes the RZSS look like the bad guys. It appears that the zoos immediate neighbours are in support of the zoo's plans. Plans which are effectively now on hold and, as Kifaru says, are visionary.
When taken as a visitor attraction alone it is second only to Edinburgh Castle in Scotland. Taken as a whole entity, and as a major part of RZSS, Edinburgh Zoo, its staff and volunteers are probably some of the most passionate, committed and visionary people I have come across (even if I do say so as a volunteer myself).
Back to pandas, there are a number of reasons the RZSS want pandas, from my understanding. First off, they are such an iconic species to have in a zoo. The income it would generate, not only for the zoo but Edinburgh and Scotland as a whole is incredible. The most important thing, though, is the ability to show a key species in research and breeding of endangered species. People know about pandas and recognise them as the WWF logo. They are an ideal way to educate people on the subject and science of conservation, as has been done with Budongo Trail and chimpanzees.
Edinburgh Zoo and the Royal Zoological Society of Scotland deserve all the support they can get. They continually meet and exceed every requirement and target given to them and less successful organisation, like the council, seem to kick them in the teeth!
It is my personal belief the the RZSS will have pandas in Scotland, they will remain on the same site in Edinburgh, Highland Wildlife Park will continue to become a greater attraction in the North of Scotland and in the long term the RZSS will become a greater success than ever.