As a photographer, I prefer a clear view of the animals without fences or windows in front - so this is not really ideal.
That being said, I like seeing animals from a different perspective occasionally - a raised platform allows you to see things in a different way to what you can see from ground level.
The lions (and African wild dogs?) enclosures would be much easier to see without the ugly steel fence all around the exhibits. The walkway is a decent idea, but a glass section would be a massive improvement.
I'm not a fan of glass/perspex for viewing - tends to get dirty very easily (fingerprints / noseprints from kids especially) and not ideal for viewing.
Perspex also scratches easily (and permanently) and can become cloudy. Thick glass and perspex can distort the view of the animal - not normally noticeable, but very obvious through the unforgiving lens.
This enclosure is an old one - I first saw it in 1978 and it was considered innovative back then.