You could add the ability to scan QR codes with mobile devices. Each design could be assigned a QR code and when it is scanned using a mobile device the design loads into that device and can be used for both client review / design approval (sharing with stakeholders) as well as testing.
An Example of this can be found here: https://doc.mockplus.com/?p=189
And here: https://doc.mockplus.com/?p=822
I would like this feature because I could easily share design proposals with stakeholders to gain feedback and/ / or approval to moving into the next phase of the SDLC or to edit the proposal for resubmission. This would be such a powerful capability I can’t think of a way to even rate it!
PS: Combined with an “Export to HTML” feature this feature pair could really rock the design world!