Spotify is a great tool for "standard" music listening, no doubt about that, but when you want to go a bit further, like using it in a party or review/analyze a song, it becomes too simple, insufficient, I'd say.
The main weakness is that you cannot "pre-listen" a song before adding it to the queue. And here is where Virtual DJ comes in action. VDJ is a professional DJ app, but it has also a free version for personal usage. Besides being able to "pre-listen" songs, you can set the starting/end points of a song, equalize player, change speed, and many other DJ features.
Other streaming music service allows VDJ to connect to it and I know people (like me) that have moved from Spotify to that one only because of this reason.
I'm not a professional DJ, but I use Virtual DJ for private parties and, as musician, it's also very helpful to learn or analyze songs, as you can repeat parts of a song, set cues, change speed, ....
Allowing Premium subscribers to use Spotify in other players would expand the Spotify possibilities. The sad part is that Spotify allowed VDJ to connect to it during some time last year, then it was removed.
I invite you to experiment with Virtual DJ (https://virtualdj.com/)
Thank you for your time and consideration.
Updated on 2019-05-26
Your idea has been submitted a while ago but unfortunately hasn't gathered enough kudos (100 per year). In order to keep an overview of the active & recent ideas in this forum, we will close this idea for now. However this does not mean that your idea has been declined by Spotify.
If you still feel strongly about your request, we encourage you to post your idea in a little different form again! Maybe now is the right time to receive the support of our community for your suggestion! ;)
P.S: More information about how the ideas exchange works can be found here.