It's a fair request, but there are so many areas of the OS that have small decisions like this, if there were a setting for all of them... Settings.app is already a little burdened under its own weight (though the search bar has helped a bit).

The set-up process for a new iPhone is also reaching crazy levels, with so many decisions for new users to make.

Don't really know what the solution to this is to be honest -- Linux-style config files maybe? :P