Time to put up a glass panel...
How many thousands of families with children visited this zoo without any kids falling in?
I wouldn't make any judgement based on my own visual observation. Some of the most reasonable, objective people who have weighed in on this incident have been zookeepers and gorilla handlers from other zoos -- who have all pointed out that a zoo is required to meet specific design and safety standards for the protection of both the animals and the visitors.
Of course, this just means that the design/safety standards will probably be upgraded ... which is really no different than a stupid warning label on a cup of coffee from McDonald's.