did anyone notice that in the power armor customization that you can change flashlights? in the new trailer with preston garvey, you can see the flashlight (on your power helmet) shining light during vats on the death claw? with the dynamic light engine in use by bethesda, it will be pretty cool to have flashlights in fallout 4.
think about this, a few areas are going to be really dark like some subways, abandoned vaults and caves. now your going to need to equip a flashlight. the flashlight should be held in your left hand but you can only use a pistol in your right.
the battery should act as your weapon CDN except you need a fission battery instead of another flashlight to repair or recharge. however weapon condition is probably not going to exist in fallout 4 so it might be different.