What I consider to be the best animated film in a long while, and my favorite film of 2016 (so far), Zootopia, like many animated films took a while to make. The concept art for the film was first released back in 2014, showing Nick surrounded by other animals and not being too happy. As a storyteller myself, I know that stories change as you work on them, make one change and many aspect die out because they no longer make sense.
Looking at the concept art for Zootopia I made an observation, I think Nick was suppose to be a spy, or when Judy was added to the story, he was suppose to be the senior officer. Her partner from the start, instead of Judy being his inspiration in joining the ZPD.
In most of the concept art, Nick is wearing a James Bond type suit, and at one point he's even doing the pose.
At one point it looks as if Nick was supposed to be the one to do the chase scene through the mouse city.
And when Judy is added into the photos, Nick is now wearing what looks like cloths most detectives wear in older television series, such as Dragnet and Colombo.
Other concept art makes it look like Humans might have existed at some point,
With these tigers being tagged in their ears, something people do to study the animals. But these also could have been used by the ZPD, much like our Cops use trackers to keep track of convicted felons.
Other concept art shows Nick's father instead of his mother, which was featured in the film walking him through the city, if I was to guess he was telling Judy why he wanted to be a cop. His father was killed in front of him while they were in the city.
Judy at switch boards,
And a mouse restaurant,
More art was found, showing the point where Nick was no longer on the right side of the law, he now wears his signature outfit, as well as a tracking collar and ear tag.
It also shows that Nick lives in his father, John Wilde's, old place of business.
Other art show's Nick riding through the Tundra part of town. With what look's like Judy is out cold on the front of his bike.
A comparison piece, showing both Nick and Judy being annoyed by the animals they are surrounded by.