What about a timer? If a set a 1s time and tap the screen, the phone will certainly move and results in blurry image.
Having a 2s, 10s (at least) timer, would certainly help getting sharper images.

Also, chosing ISO: what about have 'stops' at 100, 200, 400 up to 3200? Kind of snapping to grid while having the option to go in between those values. I find it very hard to set ISO 200 precisely.
Same for time (usual times from regular camera phones).

Moreover, yes, I also vote for feedback. I never know if I took the picture or not. Could be flashing of the screen or a little vibration to say picture's ready to view.

Thanks for this and last question, is code closed?