Surely the loose substrate offers more enrichment than grass? It's not really possible to put plants in all exhibits as primates just tend to rip them up. But I do agree that this could use more climbing structures.
After all the other comments, good and bad, the worst thing about this exhibit(which I've seen) is its size- its far too SMALL- just a little square or oblong of ground with a watermoat around it. It is NOT a good exhibit I can assure you.
Barbary Ape only lives principally on rock on the 'Rock' of Gibralter-where it was introduced. In its natural state in North Africa it is found in mountainous evergreen Cedar forests. So displaying Barbary Apes in barren rock exhibits is not correct either...
