Anyone who is familiar with Drusillas will know that its success is due to the vast array of other attractions aimed at younger visitors.
However, since the current owners took over, there has been an increase in the number of species in the animal collection. While the Ann family previously pioneered some of the first themed exhibits in this country, along geographical ('Out of Africa') or taxonomic ('World of Owls') lines, the current owners have dismantled most of the previous exhibit zones to accommodate a larger number of species.
For example, the first recipient of the Universities Federation Animal Welfare award for exhibit design in 1987 was 'Beaver Country' (which later had 'Grey Owl's Cabin' added following a fundraising campaign, with an animatronic model of the historical character set inside a replica of his Canadian log cabin adjacent to the beaver exhibit) now holds Capybara and Mara alongside the original beavers, and the old cabin has been turned into a marmoset cage.
The 'World of Owls' exhibit, which took visitors through a network of hides, and into an replica of a barn that had supposedly been damaged in the 1987 hurricane and become inhabitated by a family of Barn owls, which were visible through glass and accessed their outdoor flight through the 'damaged' side of the barn, has now added an extra flight for Great Grey owls, while Diana monkeys now occupy the site of the old barn owl aviary.
While personally I don't think nowadays the exhibits really read other than a series of (well-designed) cages and enclosures for mainly smaller mammal species, I can see how they have gone in this direction as there was little room for expansion when the original owners sold up, but most of the zoo was already highly developed. The genius of the previous owners were the highly innovative use of everyday, commonly-kept species in exhibits that told stories, about their wild habitats, or their social behaviours. Some of this can still be seen in the older exhibits still standing, but while each new exhibit seems to be a perfectly reasonable addition or improvement, IMO the storytelling magic of many of the animal exhibits at this zoo came from the Ann family.