I'm a real estate photographer. When editing photos that contain extreme amounts of highlights AND shadows (e.g. interiors of houses during daytime where the light inside is way less than the light coming in through the window, even when using copious amounts of flash to try to balance inside and outside lighting), I sometimes find myself setting Highlights all the way to -100 and Shadows to +100 and wishing they would go further. I suggest those sliders could be extended to the equivalent of +/- 150 or even 200 without affecting noise and colour casts, especially when using the latest batch of high-end DSLRs. Prior to LR4, I often achieved better results using a combination of the Fill Light and Brightness sliders. Real estate photographers mostly generate 800 x 600 pixel images for use on web sites, so noise isn't really an issue most of the time.