@KevinB More used to seeing more plants and less rock, for one. Also none of those fish are ones I'm used to seeing in a kelp forest tank, Leopard Sharks (Triakis semifasciata), various rockfishes (Sebastes spp), Garibaldi, Wolf Eels, and others are ones I'm used to seeing. Normally a bit better lighting too, though some of the ones I normally see have live kelp. Two examples below, from Monterey Bay Aquarium and Seattle Aquarium.
Personally I liked the kelp fronds, which were replicated pretty well, the best about this tank, as well as the fact that at least it decently sized for the fish kept.
That said, I personally feel that the kelp tank at the Rotterdam Zoo is better, looks nicer and is closer to your associations about kelp forest tanks.
@KevinB I agree it's decently sized for the fish being kept in it.
I'm not familiar with the one at Rotterdam, although I will say both aquariums I posted photos from are both handily placed on the Pacific waterfront with handy access to both fresh seawater and new specimens if need be.
With regards to access to seawater: Rotterdam is a port city and the Rotterdam Zoo actually has their own ship to collect seawater from the port. I'm not sure how Pairi Daiza does it, but they are quite a ways away from the sea so they will have to either transport it or make artificial seawater.
Specimens in Europe I assume come either from other zoos or through the trade.
