Being of the (ahem) generation that had an old-school plastic Zoo Key, tapped on the plastic Egg incubator in the Children's Farm and threw marshmallows to the Polar Bears, all I can say is that the Zoo has changed. For the better. Lush plantings, creative, participatory exhibits and nice attention to detail everywhere. The new Elephant Crossing is interesting and a drastic, drastic improvement over the old Pachyderm building.
I, personally, like that the Zoo is spread out as it provides a nice walking environment and gives you time to reflect on the many joys of life ...including that I don't have a screaming child amped up on sugar and rollng on the ground in a major melt-down.
Was so impressed, I bought a membership to help support the place. You should, too.