Another useful field would be a field for PDF attachments that would display the PDF in a wrapper or new window.

Optional icon, or thumbnail would be great. Has anyone ever come up with a PDF thumbnailer, now that would be cool. Generate thumb off the first page of the PDF.

as they are now, attachments don't work so great because they get downloaded instead of viewed.

This feature, if expanded on, could turn K2 into a formidable document mgt tool.