The Asset Library UI is missing a lot of nice to have features that would make it useful for managing a large number of images:
Ability to select multiple images for download/delete.
A detail view that would show columns such as upload date, filename, etc. Could be simialr to the content lists.
Would add:
Saving alt text/description for the asset
Ability to see where assets are used in content
Ability to update assets like you can do with the PUT request for the write api.