I can see no contradiction between applying the Auto enhance function in the current way with the intensity slider applied on a single picture and to offer the opportunity to use it in a different way with a standard setting on a collection of images. And as I wrote, for me at least, the ability to apply just default (or specified) specific adjustments one at the time on the a collection would be a great way to use automatic settings in controlled way
I also think that the option to exclude effect in addition to Levels and white balance would greatly add to the flexibility of the slider adjustment functionality.