There have been quite a number of good zoos that are astoundingly consistent in their nice exhibits, but lack anything stellar, in some cases I was able to sneak something on the list, but their are multiple great zoos without any exhibits on this list.
I agree with your statement and it makes for an interesting discussion. When I visited
GaiaZOO on my big European zoo trek in the summer of 2019, I called it a "superb zoological park" and I mentioned that the zoo had won awards in the Netherlands for its beauty. The Taiga, Limburg, Savanna and Rainforest biomes at GaiaZOO are all excellent, and I'm not sure that the zoo has a single poor exhibit anywhere. However, I don't expect a single representative enclosure from the zoo to make your Top 100 list.
Blijdorp Zoo, that great establishment in Rotterdam, has already been mentioned in this thread and it also might lack an exhibit that makes the Top 100 list. I loved my 7 hours at this zoo, with its combination of historic architecture and modern-day immersive enclosures. I spent 45 minutes inside the Oceanium and in my opinion that's long enough to be considered for a stand-alone aquarium anywhere else. Maybe other possibilities for a Top 100 exhibits list could be the new Gelada complex, or the iconic Giraffe House, or the amazing indoor Okapi facility. I loved my day at Blijdorp and consider it a world-class zoo, but is that enough for the establishment to show up on this thread? Only time will tell.
Lastly, I offer up the example of
ZOOM in Gelsenkirchen, Germany. A million people a year file through the wide pathways to experience the Alaskan, African and Asian zones. I think that the entire zoo is less than 20 years old and so the quality of exhibits is extremely impressive. The whole Alaskan section is in some ways brilliant, especially the Moose habitat with its big pool. The California Sea Lion pool is magnificent, with its impressive rockwork and underwater tunnel. The whole zoo is great, but it isn't always beloved by zoo nerds and I am doubtful whether anything from ZOOM will make the Top 100 list.
There are many other examples of great zoos such as GaiaZOO, Blijdorp and ZOOM, that are remarkably consistent and yet perhaps none of them will show up on
@lintworm's list. I really do think that if 100 zoo nerds each made a list of top exhibits, then none of the lists would be alike and that's what makes this thread unique.