Here's a thought: In Serious Sam:BFE, you could customize the graphics settings, so if you liked things bright and colourful, you could select that option to dial it up, if you didn't, you could select a more normal option, and there were also multiple greyscale and destaurated options.

Here's a video to demonstrate:

http://www.youtube.com/watch?v=cFxYkIPogj4


If Larian did something like this, then both people who want it dark and gritty, and those who don't mind bright and colourful could get what they want.