I have enjoyed this discussion from afar, but not contributed. However, this last comment is such a red rag to Ian's particular bull that I am eagerly anticipating his response!
For what it's worth, my opinion is that the policy of building impressive, visitor attracting exhibits for headlines species in London has been the right one. However, I just wish that those headlines exhibits were backed up with smaller supporting exhibits: aviaries of Indonesian birds alongside the Tigers and so on. That they are not, speaks, I think, of a lack of real engagement with The display of animals amongst some at the zoo. This is mirrored at Whipsnade. For example, The fairly recent lion enclosure there – I forget its name – is done well I think, but how much better would it be if it had other things alongside it that were appropriate (and, given the Tanzanian theming of the area, why on earth are meerkats included – put some banded mongooses in there, please!).
I think the real frustration that many of us feel with Whipsnade is that the potential is so vast. While many of the recent developments have been good, or even excellent, one could easily foresee a park with so many natural benefits (how many millions of people live within an hour's drive?) being truly outstanding. The cost of increasing the collection would be high – someone would need to look after that increased collection: salaries represent the major part of any zoo's outlay, and the size of those salaries has increased hugely since the 1960s and 1970s – but, nonetheless, I think many of us feel that ambition would be rewarded by increased numbers through the gates. It's a "build it and they will come" thing. The lesson from Europe seems to indicate this is so, with zoos in Belgium, France, and elsewhere receiving huge numbers of visitors when they have increased their collection. Some impala are a lovely start – but it is only a start!