Thanks for your polite and useful responses to all of my posts. I do agree with you regarding motion blur (including especially subject motion blur), but I just think that the useful range for settings on a phone is so narrow, that adding the complexity of full control over ISO or shutter speed would be more trouble than its worth.
I know this is an argument against choice, but in this case I believe its sensible. I dont grab for my phone over a real camera because I like the image quality - I do it because I can almost instantly capture whats in front of me. That might be a moment which quickly passes. If I had left the phone in manual I could ruin the shot and the moment could be gone before I can change the settings. For many people, this is the type of situation that they use a phone in a camera.
I would prefer to just see the iphones exposure algorithm revised to give priority to shutter speed over ISO. An alternative to this would be a switchable option that does this - something like "limit noise" or "fast motion", which would switch priority between the two.
A way to avoid making things overly complex to casual users would be to keep the built-in camera app unchanged, but open up the camera API so that third party apps can offer more control over the exposure.