Allow users to select the "List" view for attachments, which is an option available in the Old Issue View:
Anytime an issue in Jira has multiple attached files with long filenames, the current state is likely to pose a problem. Especially when many of those filenames start with the same substring of text. Since the new issue view doesn't guarantee to display the entire filename, it makes it very difficult to quickly see and understand which file is which. A thumbnail of the file is only ever useful to image attachments, whereas having a list view would be beneficial to seeing and sorting all attachments (regardless of type) by their actual filename.