The majority of the animals in Pairi are housed in OK/good enough enclosures. I'm not saying it couldn't be better, and it's a shame that Pairi doesn't use their money for these animals, but isn't it the same in Denver? The majority of the carnivores there are housed in OK/good enough enclosures.
Then, the newest area houses a few carnivores (brown bear, black bear, puma, wolves, Steller sea lions) all housed in great enclosures.
The carnivores that are housed in great enclosures are, in my opinion, American black bear, binturong, meerkat, European wolf, European brown bear, yellow mongoose, giant panda, Asian black bear, African lion, raccoon-dog, puma, raccoon, harbour seal, Steller sea lion, striped skunk, cheetah, spotted hyena, red panda, Mackenzie Valley wolf, dwarf mongoose, Asian small-clawed otter.
Animals that in a zoo with Pairi's funds should be in better enclosures are Indochinese clouded leopard (should have outdoor enclosure + be able to hide better from guests), Javan leopard (although enclosure is a lot better than in the past, it could still improve a lot), giant otter (enclosure is too small, not enough hiding opportunities), snow leopard (enclosure is kind of small, although it is appropriate imo), South African fur seal (small enclosure), white tiger (lots of concrete, no hiding opportunities, big pool though).
That makes 21 species in good-great enclosures, and 6 species in enclosures that range from appropriate to mediocre (all of which should count as bad enclosures if you take into account the kind of money Pairi has).
According to what has been said about Denver, there's three good-great enclosures there (Predator Ridge + clouded leopards) and the fishing cat enclosure looks quite bad. The rest should be appropriate, but not much more than appropriate.