The monkeys have no foliage, no grass, no natural climbing structure, and can't even swing from one tree to the next because they only have one structure that barely resembles a tree. They can basically only climb in a circle or to the edge of a branch and turn around
And "functional" is the bare minimum an animal enclosure needs, so that's not really an argument
@Mr Gharial Agree to disagree - you described nearly every single exhibit in the Lied Jungle, which is still often regarded as one of the greatest zoo exhibits in the US. The only major difference is, there's natural foliage surrounding Lied Jungle's habitats.
These are the kind of exhibits that really do highlight the differences in opinions on this site. While some much prefer large, naturalistic but inevitably fairly high-maintenance exhibits, others think functionality should be upheld over making an exhibit look great for visitors. From the latter's point of view, the ease of access for keepers and the money spent on the enclosure is more important than making it look good for the visitors, while the other side argue that the animals feel more at home in a naturalistic environment and it allows for more natural behaviours to come through.
I'm personally not the biggest fan of this exhibit. Far from terrible but aesthetically is very ugly and It just feels super out of place considering how the rest of the zoo is set up. It's very much an old-school zoo design and is perfectly fine for the animals - plenty of opportunities to climb contrary to claims made above.
This is also super nitpicky, but this island interrupts the middle of African Grasslands, that bugs me.