I'm going to do my best to try not to repeat what everyone else said. The spinner was fun but you didn't get much use of it outside of the Arbiter Grounds. How was that?
Seriously though, the spinner made me think on a more creative level than I thought I would find in Zelda. Like Axel said, this isn't an item I expected to see in Zelda. But after handling it, it quickly became one of my favorites. The boomerang, bow, and hookshot will always have a place in my heart, but their gonna have to make room.
I see the spinner going farther and farther if they decide to bring it back. It will most likely be upgraded like riding Epona was, to the point where it is not only as necessary as Epona, but you can use weapons on it like you can her.