The new update has removed the single most useful feature from the library and on Spotify in general, namely the ability to curate personalized artist specific playlists just by saving the songs or albums a user likes. I understand that, technically, I could work around this by creating a playlist for each artist that I listen to, however, I use the playlist feature to mix a variety of artists or songs together and have no interest in clogging my playlist tab with hundreds of different single artist playlists. I've been using Spotify premium for years now but unless the former library features are reinstated I will be on the lookout for a service that better serves my music listening experience and does not undo the years of work I've put into curating my library.
Spotify usually makes changes to improve the overall experience of using the app. This will naturally have a bigger impact on some areas than others, and we do understand that you're not able to use the app the same way anymore.
There is an idea about Your Library here. Make sure to check it out and vote if you agree. The more votes an idea gets, the more likely it is something will be changed or implemented.