I work in User Experience Design and would like to share some thoughts from my point of view. We all have our different ways of approaching this music app, each our individual use cases and therefore my view is obviously narrow. Please let me know what you think about the following statements.
Removing the filter and sort function from the top of the playlist let me lose complete faith in spotify. I use both features frequently for my main (800 songs) playlist and every action that took me a second scrolling up now takes a lot more time. Apart from that, it wouldnt be spotify if it worked right away, the sort handle is broken in my version. Whenever I click Sort by Artist to sort them ascending and click it again to sort it descending it is just stuck. I won't use both features anymore since they are hidden in an already overwhelmed context menu.
Rearranging Tracks in a playlist was a feature requested 5 years ago. It was implemented on Android mid 2018, which feels like mockery since Apple users got it I think at least half a year earlier. But it is in and it works (most of the times). I have not stressed it out recently but with small playlists of like 3 or 4 tracks there are still issues that occur.
How spotify is used for audiobooks is nothing less than a disaster. We already made a progress here, so spotify does know now that a song in an audiobook is not music (and it therefore should not be part of your daily mix playlists ... anymore). I was fascinated when I checked out my daily mix playlists in the beginning and a random chapter of an audiobook I listened a year ago appeared between the songs. But that was fixed after a few months so, yeah, cool.
Whenever I listen to an audiobook these days I take the whole thing and put it in a playlist that I download. I start listening and after a few chapters I want to listen to something else. So what happens when I go back to the audiobook? Where was I? I did not remember the chapter. It's 2019, did the app not save my progress? No. It did not.
A more or less working workaround looks like this: Listen to an audiobook in your own playlist, before you start anything new and leave the playlist, go to Edit Playlist and delete all chapters out. Yes individually. But wait. Spotify wouldn't be the app I am wasting my time with if they did not have another little trick to increase the difficulty of this workaround: In Edit Playlist you don't see the song you are currently listening to, so you have to remember the number of chapters that you have to delete from the playlist. Just highlight it in green and I can live with the fact that you are not able yourself to track my progress for an audiobook.
Removing items from playlists is another issue that needs improvement. As I explained in the beginning I have this huge main playlist of 800 songs. It happens every now and then, that I want to delete a song while shuffle playing through it. The easiest way would be to click the context menu of the songs I am listening now and select "remove from playlist". Unfortunately, this is not an option. This feature was requested 7 years ago and I am still waiting for it to be implemented. The same goes for albums. Sometimes you have multiple albums in a playlist. Only way to delete them is by removing the individual songs.
The loading time. Oh boy. I have a somewhat new android phone and even though I set it up only a few months ago spotify takes forever to load my playlists, the songs in my playlist etc. The easiest way to load the stuff you have downloaded already is to disable your internet connection since it seems to load recommendations for your playlists. The most frustrating message I ever received working a digital device was in the spotify android app when I wanted to add a song from one playlist to another, hit the context menu which just loaded and loaded until a little error message appeared: "Go online to see menu." I was online. Of course I was online.