Filling of PDF forms
Good enough to support 1040 IRS form.
Better annotation support
The basics of annotation tools are already present, and they work really well! But compared to other pdf viewers, the tools are quite limited and not really user friendly.
Edit PDF
Compress, merge and split PDFs. Also rearrange pages with drag and drop
Side by side view with multiple documents
Be able to split the windows vertically to show at least two documents side by side. I know I can create multiple windows but that's not as practical when you have a lot of documents open
OCR capability
Search text contained in an embedded image in any page of the PDF.
Rotate and Save
After rotating specific pages of a document, allow saving of the document with the rotated pages.
PDF Bookmark editing
Add a simple way to edit PDF bookmarks (outline)
Publish in windows app store
Digitally sign PDFs
Be able to use a token device to sign and time stamp with certificate
Bring Back EPUB Fonts/Layout Customization
Customization of fonts type and size, as well as page layout for EPUB disappeared in v3.4. Please bring it back.