Any hope PlayStation 4 owners may have had that a future update would allow them to disable the LED light built into the DualShock 4 controller was squashed by PlayStation's president of worldwide studios Shuhei Yoshida.
Asked on Twitter about the likelihood of a "future update" allowing such an action, Yoshida simply responded, "No."
The LED light on the DualShock 4 is there primarily as a tracking beacon for the PlayStation Camera, allowing the DS4 to serve as motion controls similar to the glowing orb of the PlayStation Move controller on the PS3. With no camera, the light bar doesn't have much use, except immersive purposes. Some developers try to incorporate it in their game, like Guerilla Games did with Killzone: Shadow Fall (the LED's color changes according to the player's health). Unfortunately, due to the location of the light bar, the LED is hardly noticeable.
Addressing the notion that disabling the LED light would save the DualShock 4 some battery life — one of the controller's biggest critiques — Shuhei said, "The LEDs do not use much battery." Other complaints about the light have to do with distracting reflective glares the light causes on the television screen.
Personally, I don't mind the LED light, but I understand why some would want it disabled. If you are one of the PS4 owners concerned about battery life, you may want to check out this inexpensive alternative to extending your DualShock 4's battery life.