On many occasions Sirin Labs has published Finney's motto: "To bridge the gap between the mass market and the blockchain economy". In my opinion, to really bridge the gap between Blockchain and mass market, the next Finney should be more accessible. It should feature state-of-the-art security and privacy, with a built in cold wallet, activated by a mechanical switch, with no additional screen.
It should keep Sirin Labs' DNA by maintaining a prominent Back Shield Element and concave sides (with a cool logo on them), but eliminate the top and bottom curves, which may be too expensive for a mass market smartphone. The back should be made of plastic instead of glass, and should be easily removable for maximum serviceability and customization (different people have different tastes).
Here are some primary sketches:
With Aluminum Shield Element and buttons
With black Shield Element and buttons