For many purposes like that I've successfully used the adjustment brush. Brush with clarity -100, sharpness -100 and perhaps contrast -33.
If you really want maximum control, may have to use Photoshop.
i would used the adjustment tool with clarity slider set to -100. It may take several or more brushes and so other adjustments
but as far as I know there are no blurring tools as in PS
will be interesting to hear other ways/ideas