Rebecca Sugar stated that what she wanted people to take away from the movie and Spinel's character arc was that it's alright to be a 'work in progress' and it's you who needs to want to change and get better.
Pink Diamond and Spinel are the only two gems to have been seen rotating their gem when taking a new form.
Rebecca Sugar based Spinel on a favorite stuffed rabbit that she once carelessly abandoned in her backyard as a child. Upon rediscovering it six months later, she found the toy had permanently changed after exposure to the elements. This same incident also inspired the 'Everything Stays' segment in Adventure Time.
Spinel is a throwback to early 20's/30's cartoons, in her appearance, mannerisms, and her opening musical number.
A picture of Connie dressed similarly to Lana, from Future Boy Conan, can be seen in Steven's room in the background. Rebecca and Ian have mentioned being big fans of the show.