It would be nice to have the sliders to go beyond the -100 / 100 limit, especially for HDR. Often i have to tweak a lot or paint and it is really time consuming.
Good idea, but did you know you can already do this? Select the Adjustment Brush, set the brush size as large as you can and turn off Auto Mask. Simply paint the entire image with the brush. Now you effectively have an Adjustment layer, that gives you another +100 Shadows and -100 Highlights. You can do this as many times as you like.