I always sound like a broken record on this issue, but I have yet to see a convincing argument for keeping most small mammal species in indoor, reverse-lighting conditions. Some animals do require very dry air (eg Sand cats), and some benefit from high humidity, but reverse-lighting really only seems to benefit the public. I always cite Marwell's outdoor douracouli enclosure as a really good example of this; you usually get to see them looking out of their nest box, and they have, for the last decade or so, been the strongest breeding group of douracouli in any UK zoo.
The off-exhibit wing of the Clore has been closed since the rainforest lookout was opened in 2007. I don't know how long the aye-aye have been there, as the Roundhouse has been closed for almost as long. Some well-planted, spacious outdoor offshow cages have been added to the back of the building over the last couple of years, I'm hopeful the aye-aye have access to one of these.
Small guided tours in the evenings can add revenue and provide access for those members of the public more interested in seeing unusual species that the daytime crowds miss.....I see no conflict with keeping a number of these species off unsupervised public display.
You're right about updates. Animals having 'world cup' or 'halloween' themed enrichment is not news, especially when your press team repeats the trick year on year.