Для input

.directive('useFormData', function ($parse) {
    return {
      link: function (scope, element, attrs) {
        if (attrs.ngModel && attrs.value) {
          $parse(attrs.ngModel).assign(scope, attrs.value);
        }
      }
    };
});
<input type="text" ng-model="title" value="default value" use-form-data />

Для textarea

.directive('useFormData', function ($parse) {
 return {
  link: function (scope, element, attrs) {
   if (attrs.ngModel && element[0].defaultValue) {
    $parse(attrs.ngModel).assign(scope, element[0].defaultValue);
   }
  }
 };
});