We need a Drag and Drop control addin from MS as a built in feature. The "Attachments" action button open a new page when user need to select a file (multiple not allowed). We need to improve the user experience by adding custom control addins.
The control addin should reture full path, using this we can get Path, File name, File type & size. This will further used in Table 1173 Document Attachment. With file type & size we add restrictions as well. Further if we can define the type of storage like onedrive, sharepoint or DB that will be a great feature.
Similar addins are available but i believe this should be part of product in Modern UI.