As this is my local zoo I think I should probably quickly chime in with my thoughts on the subject. Overall WPZ is fantastic and still one of the best in the country, in fact in terms of immersion it is likely one of the best. And yet I and many others have had their gripes with the projects the zoo has done in the last 10-15 years. The zoo has an amazing foundation of older exhibits I honestly hope they never replace. However since the opening of the very nice penguin and jaguar exhibits in the early 2000s, far more has closed than opened, and the one major development the Banyan Wilds complex is in my opinion the worst in the entire zoo. First they closed the nocturnal house for budget reasons, then they closed the entire reptile house after a minor fire, opting to close it rather than fix or replace it. For a rainy city like Seattle indoor exhibits are an important draw for the zoo and it remains a depressing eyesore right by the entrance. From what I have heard it has gone way down their priorities list, and effectively been swept under the rug. Other than that other losses were the wild dogs, replaced with warthogs. The elephants, quite adequately replaced with Indian Rhinos, however they still occupy only half of the former elephant yard leaving a significant amount of space unused. And most recently they announced that they plan on getting rid of the hippos from the fantastic safari area, the reason they gave was that they wished to save water, however given that we are hardly a drought ridden region I find this explanation hard to understand. Yes they dont have the fancy underwater viewing with crystal clear water like San Diego, but the exhibit more than makes up for it by seemingly blending in the exhibit with the main safari in the background.
Dont get me wrong, I still love my zoo very much, however that doesnt change the worrying signs of recent developments. Much of these changes seem likely to be budget related which is understandable, and I very much hope that they can pursue more city funding in the way Portland did a number of years ago for future developments. Top of my list for developments would be to construct a doubtlessly expensive new day/night house which would definitely go a long way to improving the zoo as an attraction.