I guess I technically have *two* home zoos, since Brandywine Zoo's 20 minutes from where I live and Philly's an hour away.
Brandywine Zoo
Keep: The Madagascar exhibit. Simple, but highly well done.
Steal: Central Park's snow leopard habitat, for up the hill.
Demolish: The stone cages that hold red pandas, sandhill crane and serval.
Philadelphia Zoo
Keep: Big Cat Falls (and honestly a good chunk of the "newer" exhibits)
Steal: As far as a revamp of Bear Country goes, an amalgamation of Lincoln Park's Arctic Tundra and Nashville's Expedition Peru.
Demolish: I wouldn't demolish the Rare Animal Conservation Center as much as I would completely gut the interior and make it an Annamite Mountains Conservation Center on par with JungleWorld or Madagascar at Bronx.
May as well revisit this after visiting a couple or so new zoos/aquariums.
Brandywine Zoo
Keep: Madagascar. I stand by my initial pick for this, it's the best habitat in Brandywine from an activity and welfare standpoint. Plus, baby crowned lemurs!
Steal: Big Cat Falls from Philadelphia Zoo. While the snow leopard exhibit at Central Park is a much more consistent quality (with incredible rockwork and some solid sightlines), Big Cat Falls is a brilliant example of melding old-school exhibitry with cutting edge practices like rotation/overhead passages, with an added bonus of maximizing the amount of big cat species the zoo would have on display.
Demolish: The old stone cages (now having red panda, caracal and binturong - all of which I'd move to different habitats throughout the zoo. (The renovated pudu exhibit that Brandywine's planning on building, once the pudus ideally move to South American Wetlands at the front of the zoo, that would be veritable red panda/binturong rotation space, and Blue the caracal could go into Squeakers the bobcat's exhibit.))
Philadelphia Zoo
Keep: Reptiles and Amphibians. Honestly I would keep a majority of the zoo's newer exhibits, though I would modify them a touch - the exhibit I'd touch the least would be Reptiles and Amphibians. Its ability to maximize its collection while presenting its animals in a fun and engaging way (the cobra temple especially, though it makes less sense without cobras) paved the way for more and more inventive ways of connecting the public with ectotherms. Philly's Reptiles and Amphibians walked so the LAIR could RUN.
Steal: Rivers' Edge from Saint Louis Zoo. A masterclass in providing optimized habitats for pachyderms in an urban (to an extent) environment. Rhinos and hippos would both get stellar new homes, elephants would (ideally) return, and even carnivores like cheetahs would get brand new digs. That could also mean the return of species like maned wolves, giant anteater, capybara, dwarf mongoose, I could go on. Water is Life, the giant otter, red panda and vampire bat exhibits would make a lot more sense as a bookend!
Demolish: I wouldn't demolish African Plains as much as I would heavily restructure it. Keep Tony the rhino and the zebras' yard with some touch-ups rockworkwise, the giraffe space gets expanded into The Phase, Cindy and Unna the hippos' habitat, and Bird Lake, badabingbadaboom. Southern end of the zoo too if Philly wanted to take the Rivers' Edge idea to the next level.