Darinp2 has lots of data on the HVS including stuff from NASA, and he's done some experimenting so he can probably tell you what you want to know.
I have seen the Epson laser pj (LS1000?) and that does a very good fade to black which I initially found a little uncomfortable (complete blackout in the room), but can certainly add something to a movie if they want to add a claustrophobic element (and would be great with 3D audio), and I think that would be more beneficial than brighter images with respect to movie immersion. If HDR can give us a more 3D looking image (without the need for glasses), then that would be a good thing too, but I'm not sure we need very bright, almost blinding images that might be physically rather than psychologically uncomfortable. That's just an opinion btw, but would like to see those things to see if it does add something - maybe more realism like you say when we drive into direct sunlight, which would make us wince and look away - a kind of visual tactile element.
At the moment, with those images and the comments from those who have seen it, I get the impression that it looks like HDR may be compressing the dynamic range of a pj into two thirds of what it can achieve for normal viewing, and saving the upper third and higher brightness for the brighter elements to make HDR work. It also looks like it's not adapting the gamma so it's dulling the image down and crushing detail so that's a negative thing which needs fixing.
I'm sure it'll look great when it's been fully understood by the mastering people as well as how to present it by the display manufacturers, but at the moment it just seems a bit of a mess doing more harm than good. The content that is out there can't even be played by displays that are supposedly up to spec, so perhaps it's the content that is at fault at the moment. Some of the early BDs were a bit crap until they got the hang of things, so I guess this is no different. but it just seems different this time.
Because of that, I've not really been following the current technical aspects of the new standards as so far there seems to be a lot of confusion about what we should be getting and who and what can achive these specs, or even partial specs, and it just seems like a lot of 'noise' at the moment, especially with some people claiming some things as fact on how it works and then a day later saying they were wrong and now this is how it works, so a lot of confusion out there right now from some people that also appears to be visible in the content. Admitted it's early days, but I can't say I remember anything like this before in the last 15 years. It's nothing unusual on forums I guess with people being excited about the next best thing, but this, along with the rest of the new specs for UHD just seems to be the biggest changes and the biggest mess of them all since I got into this hobby.
Not a rant, just a disappointed perception.
AOOTTFITR...