In Blizzard's previous judgments of darker fan renderings, Diablo III designer Jay Wilson stressed that desaturated color made it more difficult to identify on-screen objects and therefore reduced the ease of play. The author of the video below feels that he addresses these concerns while still giving the game a "darker" ambiance.
Wilson also noted that some other fan renderings sported effects that certainly looked pretty, but aren't possible in the current engine.
Steve's Take: At this point it is really just getting painful, but for all the nerds in a huff over this stuff, finally seeing the game in motion with these alleged color "improvements" was worth a look.
Diablo 2, which came out about a decade ago, actually has gamma and brightness controls within the video menus. So you can tell even back then Blizzard was dealing with color issues with the franchise. Probably more due to inconsistency in color reproduction of CRTs back then, but they were aware of it and addressed it. It really wouldn't be terribly surprising to see one or two other video options in Diablo 3.
Diablo 3 is gonna kick ass