Very interesting news! If Planckendael again can pull off something alike the bonobo enclosure, they'll undoubtly have another great crowd pleaser. In contrast to @KevinB, I'm not all that said that the tropical walkthrough will be sacrificed for orangutans. I found it relatively underwhelming in comparison to other parts of the zoo.
It may however mean the loss of many birds, small mammals and maybe even the only reptile outside the little Australia house, reducing the collection's diversity. I hope that there'll be some room for a supporting cast, though looking at the bonobo enclosure I somehow doubt it.
More detailed plans are revealed last week and it appears that the orangs will be housed in a separate and new building, attached to and built in front of the Asia Greenhouse. There will be 5 (each between 300 and 400 m²) islands and the zoo intend to keep the orangs with the black-crested macaques and the gibbons.
The outside aviary between the greenhouse and the restaurant will be moved tot the other (lion) side; so far there’s no indication about the species it will hold.
These plans do not exclude in anyway the holding of birds, small mammals and reptiles in the main hall (although nothing is mentioned).
I hope for Pongo abelii.
Last weekend for the first time a bonobo was born in the new bonobo house that opened this summer. Female Djanoa has given birth, the gender of the baby is not yet known.
I think the ball should never have gone up. Animals escape sometimes their habitats (through people mistakes, or technical malfunctions), but it happens. It really is not a big deal when it happens, and sometimes gives funny newspaper headlines. But as long as there are no major errors it can and will for sure happen again.
I think there will soon be harsh reactions and serious consequences for Planckendael. I can't imagine other zoos being happy about what happened, and the animal welfare authorities are probably not going to let this slide either.