Being able to see a list of all of the Albums you have in "Your Library" that you have made "Available Offline" would be extremely helpful.
The wide range of music available on spotify (thank you) is great, but because there is so much I try to save the albums I enjoy to my library so they won't be lost to memory. This is a great place to organize my favorites, but whenever I'm traveling and don't want to (or cannot) use data it would be nice to have my tracks available offline organized in one place instead of having to sift through all of the albums looking for small green arrows by the name.
Not a huge issue, but I believe a lot of people might like to have this option made available.
You can already filter by offline content. When you're inside your album list, just scroll all the way to the top to reveal a filter icon. Click it and choose Downloads. 😉