I was wondering that too, but with the new Asian exhibits opening in 2011, the orangs will be getting a new exhibit along with some Siamangs. Hopefully they will have lots of climbing structures.
The orangutans will definitely be getting a brand new habitat in a different section of the zoo, and I'm curious as to what the zoo will do with the old enclosure. There are gorillas and chimpanzees as part of the Great EscApe complex so maybe the zoo will simply open up another exhibit to either one of those ape species.
The Asian exhibit is apparently still opening in 2011, and may have komodo dragons, clouded leopards, red pandas, indian rhinos, asian elephants, sun bears, orangutans and siamangs. I'm not sure where it will be exactly on the zoo map...
...but by the Great EscApe could be a possibility even though there is not a lot of space in that area. The Great EscApe service road/facilities seem to be adjacent to the new Asian area, but then what will happen to the Pachderm building? The asian elephants and indian rhinos will go to new paddocks, but that still leaves the black rhinos and pygmy hippos in that area. Either way, along with the Children's Zoo in 2010 this zoo should cement its status as one of the 10 best in North America.
I understand now, as the Oklahoma City Zoo is basically doing what the San Diego Zoo did, only on a smaller scale. San Diego demolished most of Horn and Hoof Mesa in favour of Elephant Odyssey, and in Oklahoma the upcoming construction means that probably 9 hoofstock paddocks will disappear. Will some of the impressive hoofstock collection (including Somali wild ass) move closer to the pachyderm area?