A follow-up post from DICE senior programmer Mikael Kalms says he must retract his recent statement that an option to turn off color grading would be included in the next client patch for Battlefield 3 (thanks Joao). Here's the reasoning:

After discussing this further with my colleagues, we have decided to not implement this feature. This is the studio’s take on this matter, and I support this decision:

"As a studio, it is extremely important for us at DICE to have a unique identity in our games, not only from a gameplay perspective, but visually as well. While we appreciate that some players might want a slightly different look to the game, we are proud of the visual identity of Battlefield 3 and do not wish to change it."

I apologize for getting anybody’s hopes up, and if you have any further questions on this subject, I will refer back to the above statement.