@devilfish: What was your opinion of this new exhibit? There is still a lot of mock-rock in the enclosure and the area with natural substrate is not very large at all.
It's a nice exhibit. I didn't feel it was amazing, especially considering that there are only three animal enclosures (polar bear enclosure, seabird aviary and seal pool). The land area certainly isn't the main attraction but I liked how there were several underwater viewing vantage points, and it's not possible to see the entire pool from any one viewing area, making the exhibit seem bigger (and perhaps slightly disorientating) as you go round and see more of the pool. The land area is 720 sq. metres, which I don't feel is too bad. I liked the feature that the polar bears can go down into the moat, and I didn't find the mock rock too unsightly. The interpretive signage is absolutely brilliant, and visitors can easily spend hours enjoying the exhibit experience; I saw many who would watch the polar bear for quite some time at each viewing window, even though it was only swimming in circles. The exhibit makes for a good display of the species and does it well. It's not mind-blowing, but I wouldn't have been disappointed if this was my main reason for visiting the zoo.
The land area is slightly bigger than it appears in this picture but having been here a couple of times and having a fairly high opinion of the complex overall, I do think they missed an opportunity in making the land area bigger.
There isn't a lot of (or any) natural rock in the Copenhagen area, so the mock rock is hard to avoid. Unless you go for the completely artificial concrete look, like in the baboon enclosure (which is ugly as h..., but works well for the monkeys).