My suggestions to Spotify:

1. Embrace the Blockchain Music Project (DotBC): Get the royalties right and build a system that the long tail of music producers and creators want to participate in. If artists actually felt that they had a chance of being rewarded for participation, the amount of sharing would be epic. Right now your system is built on 100 winners and a million losers.
2. Create REAL social interactions. Let’s face it, the social network part of Spotify seriously stinks. Yes, people can, through bizarre alchemy, find each other but there is nothing that helps people create meaningful connections. Basically, Spotify has reduced it’s utility to only a cheap means for people to access and listen to music alone and with no way to meaningfully communicate with other fans etc.
3. Reward active participants. If I share Spotify content across my social media and people listen, reward me. Give me, the consumer, an active stake in your company. Make me an evangelist, reward me when, for instance, my Prince tribute playlist gets over 300 subscribers. I create value for your business model, reward me and I will be much more passionately involved in your product. You can do this a million ways, at the very least you should give all active sharers/users automatic premium if they generate more value in listens than the cost of premium. And if the label partners balk, explain network effects.
4. Charge your advertisers more money. I don’t know this for sure but Spotify often comes across as a group of Blackbeard’s crying Pirate. If you are really parsing pennies, change the business model.
5. Make the interface more user friendly (black on black, for instance, makes it hard to even see the sliders).
6. Actually listen and interact with your core users. Has anyone else ever tried to get in touch with Spotify? Good luck! I have talked to them a few times but it is not easy.

Now, all that said, I would miss Spotify, but I also miss the time when musicians actually made money creating music that people listened to.