The pupil adjustment effect is much too slow, and your eyes are already doing it outside the game when the ingame lighting changes, which makes it superfluous and annoying.
Bloom on the other hand makes the game look blurry and dreamlike instead of realistic, and just looks silly. Our brain has sophisticated mechanisms built in just to ignore the blurriness and defects in our own vision, so getting them forced on you by the game is fairly frustrating.
I've been trying to disable these two effects since I got the game around the launch day, but haven't found a proper way to do this. The HDR settings in the .ini-files don't seem to affect much of anything. The pupil dilation effect looks to be tied to the Imagespaces the game uses for lighting and weather, and there seems to be no way to disable it outside of editing the Imagespaces individually.
Bloom might work similarly, as the bloom settings in the .inis seem to do jack.
Anyone looked at disabling this stuff? It's my number 2 annoyance after the horribad UI, which has luckily gotten improved majorly by modders by now. Would be nice to get rid of this [censored], as "HDR" is something I tend to disable as a first thing in any game I play, and for whatever reason that's not possible with Skyrim.
On a positive note, at least they didn't include lens flares...