A couple of workflows come to mind...
(1) Ace reports are an input when doing follow-up accessibility work in
SMART. You upload the report.json from Ace to get started. Granted, the current system works fine for a publisher working one book at a time. However, dumping reports into unique subfolders would allow publishers, curators, etc. to work asynchronously.
(2) The discussion about custom columns and the fact that this is an editor plugin actually got me salivating for a manage-by-exception workflow where I could have Ace as a library-level plugin to perform batch checks against selected books or the whole library and add a pass/fail to a custom column.
In my case, I'm trying to work through the whole library of a family member who is losing her vision and relying on Assistive Technology to enjoy her books. It is quite time-consuming with lots of repetitive tasks that I'm increasingly eager to batch / automate as much as possible.
I imagine making Ace into a library-level plugin would be a daunting task though.