I would've let you use a flashlight while holding a gun, albeit, the flashlight would have VERY limited time (maybe 20 seconds before it died).
I completely agree with that, and was thinking the same thing. Sort of similar to the infra-red goggles in Farcry, in that they run down in a few seconds, then charge back up again.
Imagine the tension then, far greater than just bumbling around in complete darkness.
You enter a new room, hear a load of scary sounds, and suddenly your torch starts to flicker, then off. And you then have to wait for a few seconds to charge back up. Surely, thats a lot more tense than keep swapping between torch and gun ?
And pretty much everything Fatman said, I agree with.