This seems important since when we have inputs that pend updates using ng-model-options we still want all changes to take place immediately if the form is submitted.

I'll have a PR ready with this probably this week.

This can be also very useful since ppl will no longer need to have shadow copies of objects while they let users edit an object in a form. The changes will be flushed only when the form is submitted if they use something like {updateOn: 'submit', validateOn: 'default'} (see #7016)