Your proposal is to decrease the dynamic range of the display. This will certainly achieve the goal of making switching between light and dark backgrounds more comfortable, but makes it worse for viewing photographs or videos. It's also not ideal when doing any amount of design, as most viewers won't have their screens set up the same way.
Photographs and videos seems allright to me, maybe I'm just used to it. I like that the dark regions are visible (esp. when IPS LCDs have not that great blacks due to the backlight).
I always hated it on CRTs where photographs were too dark, had to use a really big gamma correction on them (2.5), I guess I've got used to it from these times because it was a necessity to be compatible with LCDs.
The photos and videos are more dull when compared to a reality, but consistent with other stuff on the screen. I have no problem doing color stuff for things like textures, website design etc. The relative comparison to other material is enough for me. I've been working with graphics designers with calibrated monitors and didn't get any complaints.
But I don't do anything that requires working with calibrated monitors, like printing. Though it's hard to tell if it would be an issue. You need to do test prints anyway. You have to use specific named colors (Pantone). Based on that you can just imagine how it would look, no need to have it precisely shown all the time.
