If you do go, go to the pangolins around their feeding time (shown at the exhibit but was 1.30pm both days we were there) - the lights are turned on for a short while, the animals are active and the keepers may start waving the pangolins about (I was standing next to Tim when this was taken!). They're well worth seeing.
It's also worth going to the exhibit around 10.15am - but mainly because this is the time of the elephant bath directly opposite!
To be fair, Gondwanaland is a very impressive structure, attractively landscaped and beautifully planted - and I expect it will look better in a few years once the vegetation has matured.
However, for such a large, expensive development there are not many animals to see and, although the individual enclosures look superficially attractive amongst all the luxuriant vegetation, some of them are actually quite small. Personally I prefer to see animals like guenons, small cats, Malayan tapirs and pygmy hippos with access to outdoor enclosures, instead of being kept permanently indoors.
This is not a criticism of Leipzig Zoo (which on the whole I like very much) as I feel much the same about similar large tropical houses in other zoos too.