The other big one that I just remembered:

Multiple labels.

Especially in the punk/hardcore world, but definitely elsewhere, too, multiple labels co-release a record together and they are all credited as releasing it. Right now the input for this is okay, but it takes some playing around.

Example for an album that 2 labels co-released:

Label: LABEL / OTHER LABEL
Number: 001 / 123

Would look like this on the finished page:

LABEL / OTHER LABEL / 001 / 123

Whereas if only LABEL released it, it would look like: LABEL 001

One way to get around it is on input:

Label: LABEL
Number: 001 / OTHER LABEL 123

Which translate on the finished page to: LABEL 001 / OTHER LABEL 123, but then makes a mess of the "Number" textbox.

It would be nice to have an option for multiple labels and catalog numbers